System for Placement of a Catheter Including a Signal-Generating Stylet

ABSTRACT

An integrated catheter placement system for accurately placing a catheter within a patient&#39;s vasculature is disclosed. In one embodiment, the integrated system comprises a system console, a tip location sensor unit for temporary placement on the patient&#39;s chest, and an ultrasound probe. The tip location sensor senses a field produced by a stylet disposed in a lumen of the catheter when the catheter is disposed in the vasculature. The ultrasound probe ultrasonically images a portion of the vasculature prior to introduction of the catheter. ECG signal-based catheter tip guidance is included to enable guidance of the catheter tip to a desired position with respect to a node of the patient&#39;s heart. The stylet includes an electromagnetic coil that can be operably connected to the sensor unit and/or console through a sterile barrier without compromising the barrier. The stylet can also be wirelessly connected to the sensor unit and/or console.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.12/715,556, filed Mar. 2, 2010, which claims the benefit of U.S.Provisional Application No. 61/156,842, filed Mar. 2, 2009, and titled“System For Placement Of A Catheter Including A Signal-GeneratingStylet,” and is a continuation-in-part of U.S. patent application Ser.No. 12/426,175, filed Apr. 17, 2009, and titled “Systems and Methods forBreaching a Sterile Field for Intravascular Placement of a Catheter,”which is a continuation-in-part of U.S. patent application Ser. No.12/323,273, filed Nov. 25, 2008, now U.S. Pat. No. 8,388,541, titled“Integrated System for Intravascular Placement of a Catheter,” whichclaims the benefit of the following U.S. Provisional Applications: No.61/095,921, filed Sep. 10, 2008, and titled “System and Method forPlacing a Catheter Within a Vasculature of a Patient;” No. 61/095,451,filed Sep. 9, 2008, and titled “Catheter Assembly Including ECG andMagnetic-Based Sensor Stylet;” No. 61/091,233, filed Aug. 22, 2008, andtitled “Catheter Including Preloaded Steerable Stylet;” No. 61/045,944,filed Apr. 17, 2008, and titled “Drape-Breaching Electrical Connector;”and No. 60/990,242, filed Nov. 26, 2007, and titled “IntegratedUltrasound and Tip Location System for Intravascular Placement of aCatheter.” Each of the afore-referenced applications is incorporatedherein by reference in its entirety.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed toan integrated catheter placement system configured for accuratelyplacing a catheter within the vasculature of a patient. The integratedsystem employs at least two modalities for improving catheter placementaccuracy: 1) ultrasound-assisted guidance for introducing the catheterinto the patient's vasculature; and 2) a tip location system (“TLS”), ormagnetically-based (e.g., via permanent magnet(s) or electromagnet(s))tracking of the catheter tip during its advancement through thevasculature to detect and facilitate correction of any tip malpositionduring such advancement.

In one embodiment, the integrated system comprises a system consoleincluding a control processor, a tip location sensor unit for temporaryplacement on a portion of a body of the patient, and an ultrasoundprobe. The tip location sensor senses a magnetic field of a styletdisposed in a lumen of the catheter when the catheter is disposed in thevasculature. The ultrasound probe ultrasonically images a portion of thevasculature prior to introduction of the catheter into the vasculature.In addition, the ultrasound probe includes user input controls forcontrolling use of the ultrasound probe in an ultrasound mode and use ofthe tip location sensor in a tip location mode.

In another embodiment, a third modality, i.e., ECG signal-based cathetertip guidance, is included in the system to enable guidance of thecatheter tip to a desired position with respect to a node of thepatient's heart from which the ECG signals originate. Various means forestablishing a conductive pathway between a sterile field of the patientand a non-sterile field to enable passage of ECG signals from thecatheter to the tip location sensor are also disclosed. Such meansinclude, for example, connector schemes that establish the conductivepathway through a perforation defined in a sterile barrier, such as asurgical drape, wherein the perforation is isolated by the connectorscheme so as to prevent contamination or compromise of the sterile fieldof the patient.

In one embodiment, the tip location sensor stylet includes anelectromagnetic coil that can be operably connected to the sensor unitand/or console through a sterile barrier without compromising thebarrier and the sterile field it at least partially defines. The styletcan also be wirelessly connected to the sensor unit and/or console.

These and other features of embodiments of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of embodiments of theinvention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the present disclosure will be renderedby reference to specific embodiments thereof that are illustrated in theappended drawings. It is appreciated that these drawings depict onlytypical embodiments of the invention and are therefore not to beconsidered limiting of its scope. Example embodiments of the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a block diagram depicting various elements of an integratedsystem for intravascular placement of a catheter, according to oneexample embodiment of the present invention;

FIG. 2 is a simplified view of a patient and a catheter being insertedtherein with assistance of the integrated system of FIG. 1;

FIGS. 3A and 3B are views of a probe of the integrated system of FIG. 1;

FIG. 4 is a screenshot of an ultrasound image as depicted on a displayof the integrated system of FIG. 1;

FIG. 5 is a perspective view of a stylet employed in connection with thesystem of FIG. 1 in placing a catheter within a patient vasculature;

FIG. 6 is an icon as depicted on a display of the integrated system ofFIG. 1, indicating a position of a distal end of the stylet of FIG. 5during catheter tip placement procedures;

FIGS. 7A-7E depict various example icons that can be depicted on thedisplay of the integrated system of FIG. 1 during catheter tip placementprocedures;

FIGS. 8A-8C are screenshots of images depicted on a display of theintegrated system of FIG. 1 during catheter tip placement procedures;

FIG. 9 is a block diagram depicting various elements of an integratedsystem for intravascular placement of a catheter, according to anotherexample embodiment of the present invention;

FIG. 10 is a simplified view of a patient and a catheter being insertedtherein with assistance of the integrated system of FIG. 9;

FIG. 11 is a perspective view of a stylet employed in connection withthe integrated system of FIG. 9 in placing a catheter within a patientvasculature;

FIGS. 12A-12E are various views of portions of the stylet of FIG. 11;

FIGS. 13A-13D are various views of a fin connector assembly for use withthe integrated system of FIG. 9;

FIGS. 13E-13F are various views of a tether connector for use with thefin connector assembly shown in FIGS. 13A-13D;

FIGS. 14A-14C are views showing the connection of a stylet tether andfin connector to a sensor of the integrated system of FIG. 9;

FIG. 15 is a cross sectional view of the connection of the stylettether, fin connector, and sensor shown in FIG. 14C;

FIG. 16 is simplified view of an ECG trace of a patient;

FIG. 17 is a screenshot of an image depicted on a display of theintegrated system of FIG. 9 during catheter tip placement procedures;

FIG. 18 is a cross sectional view of a fin connector includingelectrical contacts configured in accordance with one embodiment;

FIGS. 19A and 19B are simplified views of an electrical contactretention system for engagement of a tether connector with a finconnector, in accordance with one embodiment;

FIGS. 20A-20C are various views of one embodiment of a fin connector anda tether connector for establishing a signal pathway through a sterilebarrier in connection with use of the integrated system describedherein;

FIGS. 21A and 21B are various views of a connector for electricallyconnecting ECG electrodes to a sensor of the integrated system,according to one embodiment;

FIGS. 22A-22C are various views of one embodiment of a fin connector anda tether connector for establishing a signal pathway through a sterilebarrier;

FIGS. 23A and 23B are cross sectional views of a connector system forestablishing a signal pathway through a sterile barrier, according toone embodiment;

FIG. 24 is a simplified side view of a connector system for establishinga signal pathway through a sterile barrier, according to one embodiment;

FIGS. 25A and 25B are simplified side views of a connector system forestablishing a signal pathway through a sterile barrier, according toone embodiment;

FIGS. 26A and 26B are cross sectional views of a connector system forestablishing a signal pathway through a sterile barrier, according toone embodiment;

FIG. 27 is a simplified view of a connector system for establishing asignal pathway through a sterile barrier, according to one embodiment;

FIG. 28 is a perspective view of stylet including a sterile shield foruse with the connector system shown in FIG. 28, according to oneembodiment;

FIGS. 29A and 29B are simplified views of the ECG module of FIG. 27,including a connector system for establishing a signal pathway through asterile barrier, according to one embodiment;

FIG. 30 is a simplified view of a connector system for establishing asignal pathway through a sterile barrier, according to one embodiment;

FIG. 31 is a simplified view of a connector system for establishing asignal pathway through a sterile barrier, according to one embodiment;

FIG. 32 is a simplified view of elements of a connector system forestablishing a signal pathway through a sterile barrier, according toone embodiment;

FIG. 33 is a view of a means for establishing a conductive pathwaybetween sterile and non-sterile fields, according to one embodiment.

FIG. 34 is a view of another means for establishing a conductive pathwaybetween sterile and non-sterile fields, according to one embodiment.

FIGS. 35A-C depict exemplary P-wave waveforms.

FIG. 36 is a view of a sensor retro-fitted with a wireless module,according to one embodiment.

FIG. 37 is a view of a retention feature for a connector, according toone embodiment.

FIG. 38 is a simplified view of a patient and a catheter being insertedtherein with the assistance of a catheter placement system, according toone embodiment;

FIG. 39 is a perspective view of an untethered stylet configured inaccordance with one embodiment;

FIG. 40 is a partial cross sectional view of a distal portion of thestylet of FIG. 3;

FIG. 41 is a simplified block diagram of a module portion of theuntethered stylet of FIG. 3, together with associated components of theconsole of FIG. 38;

FIG. 42 is a simplified diagram showing various components employed insynchronizing a pulse signal frequency between a wireless stylet and aconsole of the system of FIG. 38;

FIGS. 43A-43B are perspective views of the sensor unit of FIG. 10 and atethered stylet, showing one possible connective scheme therebetween inaccordance with one embodiment; and

FIG. 44 is a partial cross sectional view of the connective scheme ofthe sensor unit and tethered stylet, according to one embodiment.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exemplaryembodiments of the present invention, and are neither limiting nornecessarily drawn to scale.

FIGS. 1-44 depict various features of embodiments of the presentinvention, which is generally directed to a catheter placement systemconfigured for accurately placing a catheter within the vasculature of apatient. In one embodiment, the catheter placement system employs atleast two modalities for improving catheter placement accuracy: 1)ultrasound-assisted guidance for introducing the catheter into thepatient's vasculature; and 2) a tip location/navigation system (“TLS”),or magnetically-based tracking of the catheter tip during itsadvancement through the tortuous vasculature path to detect andfacilitate correction of any tip malposition during such advancement.The ultrasound guidance and tip location features of the present systemaccording to one embodiment are integrated into a single device for useby a clinician placing the catheter. Integration of these two modalitiesinto a single device simplifies the catheter placement process andresults in relatively faster catheter placements. For instance, theintegrated catheter placement system enables ultrasound and TLSactivities to be viewed from a single display of the integrated system.Also, controls located on an ultrasound probe of the integrated device,which probe is maintained within the sterile field of the patient duringcatheter placement, can be used to control functionality of the system,thus precluding the need for a clinician to reach out of the sterilefield in order to control the system.

In another embodiment, a third modality, i.e., ECG signal-based cathetertip guidance, is included in the integrated system to enable guidance ofthe catheter tip to a desired position with respect to a node of thepatient's heart from which the ECG signals originate. Such ECG-basedpositional assistance is also referred to herein as “tip confirmation.”

Combination of the three modalities above according to one embodimentenables the catheter placement system to facilitate catheter placementwithin the patient's vasculature with a relatively high level ofaccuracy, i.e., placement of the distal tip of the catheter in apredetermined and desired position. Moreover, because of the ECG-basedguidance of the catheter tip, correct tip placement may be confirmedwithout the need for a confirmatory X-ray. This, in turn, reduces thepatient's exposure to potentially harmful x-rays, the cost and timeinvolved in transporting the patient to and from the x-ray department,costly and inconvenient catheter repositioning procedures, etc.

As the ECG signal-based modality includes a need for passing ECG signalsfrom a catheter assembly disposed in a sterile field of a patient to adata-receiving component of the system disposed in a non-sterile field,embodiments of the present invention are further concerned with variousconnector systems for establishing a conductive pathway through asterile barrier separating the sterile and non-sterile fields.

For clarity it is to be understood that the word “proximal” as usedherein refers to a direction relatively closer to a clinician, while theword “distal” refers to a direction relatively further from theclinician. For example, the end of a catheter placed within the body ofa patient is considered a distal end of the catheter, while the catheterend remaining outside the body is a proximal end of the catheter. Also,the words “including,” “has,” and “having,” as used herein, includingthe claims, shall have the same meaning as the word “comprising.”

Reference is first made to FIGS. 1 and 2 which depict various componentsof a catheter placement system (“system”), generally designated at 10,configured in accordance with one example embodiment of the presentinvention. As shown, the system 10 generally includes a console 20,display 30, probe 40, and sensor 50, each of which is described infurther detail below.

FIG. 2 shows the general relation of these components to a patient 70during a procedure to place a catheter 72 into the patient vasculaturethrough a skin insertion site 73. FIG. 2 shows that the catheter 72generally includes a proximal portion 74 that remains exterior to thepatient and a distal potion 76 that resides within the patientvasculature after placement is complete. The system 10 is employed toultimately position a distal tip 76A of the catheter 72 in a desiredposition within the patient vasculature. In one embodiment, the desiredposition for the catheter distal tip 76A is proximate the patient'sheart, such as in the lower one-third (⅓^(rd)) portion of the SuperiorVena Cava (“SVC”). Of course, the system 10 can be employed to place thecatheter distal tip in other locations. The catheter proximal portion 74further includes a hub 74A that provides fluid communication between theone or more lumens of the catheter 72 and one or more extension legs 74Bextending proximally from the hub.

An example implementation of the console 20 is shown in FIG. 8C, thoughit is appreciated that the console can take one of a variety of forms. Aprocessor 22, including non-volatile memory such as EEPROM for instance,is included in the console 20 for controlling system function duringoperation of the system 10, thus acting as a control processor. Adigital controller/analog interface 24 is also included with the console20 and is in communication with both the processor 22 and other systemcomponents to govern interfacing between the probe 40, sensor 50, andother system components.

The system 10 further includes ports 52 for connection with the sensor50 and optional components 54 including a printer, storage media,keyboard, etc. The ports in one embodiment are USB ports, though otherport types or a combination of port types can be used for this and theother interfaces connections described herein. A power connection 56 isincluded with the console 20 to enable operable connection to anexternal power supply 58. An internal battery 60 can also be employed,either with or exclusive of an external power supply. Power managementcircuitry 59 is included with the digital controller/analog interface 24of the console to regulate power use and distribution.

The display 30 in the present embodiment is integrated into the console20 and is used to display information to the clinician during thecatheter placement procedure. In another embodiment, the display may beseparate from the console. As will be seen, the content depicted by thedisplay 30 changes according to which mode the catheter placement systemis in: US, TLS, or in other embodiments, ECG tip confirmation. In oneembodiment, a console button interface 32 (see FIGS. 1, 8C) and buttonsincluded on the probe 40 can be used to immediately call up a desiredmode to the display 30 by the clinician to assist in the placementprocedure. In one embodiment, information from multiple modes, such asTLS and ECG, may be displayed simultaneously, such as in FIG. 17. Thus,the single display 30 of the system console 20 can be employed forultrasound guidance in accessing a patient's vasculature, TLS guidanceduring catheter advancement through the vasculature, and (as in laterembodiments) ECG-based confirmation of catheter distal tip placementwith respect to a node of the patient's heart. In one embodiment, thedisplay 30 is an LCD device.

FIGS. 3A and 3B depict features of the probe 40 according to oneembodiment. The probe 40 is employed in connection with the firstmodality mentioned above, i.e., ultrasound (“US”)-based visualization ofa vessel, such as a vein, in preparation for insertion of the catheter72 into the vasculature. Such visualization gives real time ultrasoundguidance for introducing the catheter into the vasculature of thepatient and assists in reducing complications typically associated withsuch introduction, including inadvertent arterial puncture, hematoma,pneumothorax, etc.

The handheld probe 40 includes a head 80 that houses a piezoelectricarray for producing ultrasonic pulses and for receiving echoes thereofafter reflection by the patient's body when the head is placed againstthe patient's skin proximate the prospective insertion site 73 (FIG. 2).The probe 40 further includes a plurality of control buttons 84, whichcan be included on a button pad 82. In the present embodiment, themodality of the system 10 can be controlled by the control buttons 84,thus eliminating the need for the clinician to reach out of the sterilefield, which is established about the patient insertion site prior tocatheter placement, to change modes via use of the console buttoninterface 32.

As such, in one embodiment a clinician employs the first (US) modalityto determine a suitable insertion site and establish vascular access,such as with a needle or introducer, then with the catheter. Theclinician can then seamlessly switch, via button pushes on the probebutton pad 82, to the second (TLS) modality without having to reach outof the sterile field. The TLS mode can then be used to assist inadvancement of the catheter 72 through the vasculature toward anintended destination.

FIG. 1 shows that the probe 40 further includes button and memorycontroller 42 for governing button and probe operation. The button andmemory controller 42 can include non-volatile memory, such as EEPROM, inone embodiment. The button and memory controller 42 is in operablecommunication with a probe interface 44 of the console 20, whichincludes a piezo input/output component 44A for interfacing with theprobe piezoelectric array and a button and memory input/output component44B for interfacing with the button and memory controller 42.

FIG. 4 shows an example screenshot 88 as depicted on the display 30while the system 10 is in its first ultrasound modality. An image 90 ofa subcutaneous region of the patient 70 is shown, depicting a crosssection of a vein 92. The image 90 is produced by operation of thepiezoelectric array of the probe 40. also included on the displayscreenshot 88 is a depth scale indicator 94, providing informationregarding the depth of the image 90 below the patient's skin, a lumensize scale 96 that provides information as to the size of the vein 92relative to standard catheter lumen sizes, and other indicia 98 thatprovide information regarding status of the system 10 or possibleactions to be taken, e.g., freeze frame, image templates, data save,image print, power status, image brightness, etc.

Note that while a vein is depicted in the image 90, other body lumens orportions can be imaged in other embodiments. Note that the US mode shownin FIG. 4 can be simultaneously depicted on the display 30 with othermodes, such as the TLS mode, if desired. In addition to the visualdisplay 30, aural information, such as beeps, tones, etc., can also beemployed by the system 10 to assist the clinician during catheterplacement. Moreover, the buttons included on the probe 40 and theconsole button interface 32 can be configured in a variety of ways,including the use of user input controls in addition to buttons, such asslide switches, toggle switches, electronic or touch-sensitive pads,etc. Additionally, both US and TLS activities can occur simultaneouslyor exclusively during use of the system 10.

As just described, the handheld ultrasound probe 40 is employed as partof the integrated catheter placement system 10 to enable USvisualization of the peripheral vasculature of a patient in preparationfor transcutaneous introduction of the catheter. In the present exampleembodiment, however, the probe is also employed to control functionalityof the TLS portion, or second modality, of the system 10 when navigatingthe catheter toward its desired destination within the vasculature asdescribed below. Again, as the probe 40 is used within the sterile fieldof the patient, this feature enables TLS functionality to be controlledentirely from within the sterile field. Thus the probe 40 is adual-purpose device, enabling convenient control of both US and TLSfunctionality of the system 10 from the sterile field. In oneembodiment, the probe can also be employed to control some or allECG-related functionality, or third modality, of the catheter placementsystem 10, as described further below.

The catheter placement system 10 further includes the second modalitymentioned above, i.e., the magnetically-based catheter TLS, or tiplocation system. The TLS enables the clinician to quickly locate andconfirm the position and/or orientation of the catheter 72, such as aperipherally-inserted central catheter (“PICC”), central venous catheter(“CVC”), or other suitable catheter, during initial placement into andadvancement through the vasculature of the patient 70. Specifically, theTLS modality detects a magnetic field generated by a magneticelement-equipped tip location stylet, which is pre-loaded in oneembodiment into a longitudinally defined lumen of the catheter 72, thusenabling the clinician to ascertain the general location and orientationof the catheter tip within the patient body. In one embodiment, themagnetic assembly can be tracked using the teachings of one or more ofthe following U.S. Pat. Nos. 5,775,322; 5,879,297; 6,129,668; 6,216,028;and 6,263,230. The contents of the afore-mentioned U.S. patents areincorporated herein by reference in their entireties. The TLS alsodisplays the direction in which the catheter tip is pointing, thusfurther assisting accurate catheter placement. The TLS further assiststhe clinician in determining when a malposition of the catheter tip hasoccurred, such as in the case where the tip has deviated from a desiredvenous path into another vein.

As mentioned, the TLS utilizes a stylet to enable the distal end of thecatheter 72 to be tracked during its advancement through thevasculature. FIG. 5 gives an example of such a stylet 100, whichincludes a proximal end 100A and a distal end 100B. A handle is includedat the stylet proximal end 100A, with a core wire 104 extending distallytherefrom. A magnetic assembly is disposed distally of the core wire104. The magnetic assembly includes one or more magnetic elements 106disposed adjacent one another proximate the stylet distal end 100B andencapsulated by tubing 108. In the present embodiment, a plurality ofmagnetic elements 106 is included, each element including a solid,cylindrically shaped ferromagnetic stacked end-to-end with the othermagnetic elements. An adhesive tip 110 can fill the distal tip of thetubing 108, distally to the magnetic elements 106.

Note that in other embodiments, the magnetic elements may vary from thedesign in not only shape, but also composition, number, size, magnetictype, and position in the stylet distal segment. For example, in oneembodiment, the plurality of ferromagnetic magnetic elements is replacedwith an electromagnetic assembly, such as an electromagnetic coil, whichproduces a magnetic field for detection by the sensor. Another exampleof an assembly usable here can be found in U.S. Pat. No. 5,099,845entitled “Medical Instrument Location Means,” which is incorporatedherein by reference in its entirety. Yet other examples of styletsincluding magnetic elements that can be employed with the TLS modalitycan be found in U.S. application Ser. No. 11/466,602, filed Aug. 23,2006, and entitled “Stylet Apparatuses and Methods of Manufacture,”which is incorporated herein by reference in its entirety. These andother variations are therefore contemplated by embodiments of thepresent invention. It should appreciated herein that “stylet” as usedherein can include any one of a variety of devices configured forremovable placement within a lumen of the catheter to assist in placinga distal end of the catheter in a desired location within the patient'svasculature.

FIG. 2 shows disposal of the stylet 100 substantially within a lumen inthe catheter 72 such that the proximal portion thereof extendsproximally from the catheter lumen, through the hub 74A and out througha selected one of the extension legs 74B. So disposed within a lumen ofthe catheter, the distal end 100B of the stylet 100 is substantiallyco-terminal with the distal catheter end 76A such that detection by theTLS of the stylet distal end correspondingly indicates the location ofthe catheter distal end.

The TLS sensor 50 is employed by the system 10 during TLS operation todetect a magnetic field produced by the magnetic elements 106 of thestylet 100. As seen in FIG. 2, the TLS sensor 50 is placed on the chestof the patient during catheter insertion. The TLS sensor 50 is placed onthe chest of the patient in a predetermined location, such as throughthe use of external body landmarks, to enable the magnetic field of thestylet magnetic elements 106, disposed in the catheter 72 as describedabove, to be detected during catheter transit through the patientvasculature. Again, as the magnetic elements 106 of the stylet magneticassembly are co-terminal with the distal end 76A of the catheter 72(FIG. 2), detection by the TLS sensor 50 of the magnetic field of themagnetic elements provides information to the clinician as to theposition and orientation of the catheter distal end during its transit.

In greater detail, the TLS sensor 50 is operably connected to theconsole 20 of the system 10 via one or more of the ports 52, as shown inFIG. 1. Note that other connection schemes between the TLS sensor andthe system console can also be used without limitation. As justdescribed, the magnetic elements 106 are employed in the stylet 100 toenable the position of the catheter distal end 76A (FIG. 2) to beobservable relative to the TLS sensor 50 placed on the patient's chest.Detection by the TLS sensor 50 of the stylet magnetic elements 106 isgraphically displayed on the display 30 of the console 20 during TLSmode. In this way, a clinician placing the catheter is able to generallydetermine the location of the catheter distal end 76A within the patientvasculature relative o the TLS sensor 50 and detect when cathetermalposition, such as advancement of the catheter along an undesiredvein, is occurring.

FIGS. 6 and 7A-7E show examples of icons that can be used by the consoledisplay 30 to depict detection of the stylet magnetic elements 106 bythe TLS sensor 50. In particular, FIG. 6 shows an icon 114 that depictsthe distal portion of the stylet 100, including the magnetic elements106 as detected by the TLS sensor 50 when the magnetic elements arepositioned under the TLS sensor. As the stylet distal end 100B issubstantially co-terminal with the distal end 76A of the catheter 72,the icon indicates the position and orientation of the catheter distalend. FIGS. 7A-7E show various icons that can be depicted on the on theconsole display 30 when the magnetic elements 106 of the stylet 100 arenot positioned directly under a portion of the TLS sensor 50, but arenonetheless detected nearby. The icons can include half-icons 114A andquarter-icons 114B that are displayed according to the position of thestylet magnetic assembly, i.e., the magnetic elements 106 in the presentembodiment, relative to the TLS sensor 50.

FIGS. 8A-8C depict screenshots taken from the display 30 of the system10 while in TLS mode, showing how the magnetic assembly of the stylet100 is depicted. The screenshot 118 of FIG. 8A shows a representativeimage 120 of the TLS sensor 50. Other information is provided on thedisplay screenshot 118, including a depth scale indicator 124,status/action indicia 126, and icons 128 corresponding to the buttoninterface 32 included on the console 20 (FIG. 8C). Though the icons 128in the present embodiment are simply indicators to guide the user inidentifying the purpose of the corresponding buttons of the buttoninterface 32, in another embodiment the display can be madetouch-sensitive so that the icons themselves can function as buttoninterfaces and can change according to the mode the system is in.

During initial stages of catheter advancement through the patient'svasculature after insertion therein, the distal end 76A of the catheter72, having the stylet distal end 100B substantially co-terminaltherewith, is relatively distant from the TLS sensor 50. As such, thedisplay screenshot will indicate “no signal,” indicating that themagnetic field from the stylet magnetic assembly has not been detected.In FIG. 8B, the magnetic assembly proximate the stylet distal end 100Bhas advanced sufficiently close to the TLS sensor 50 to be detectedthereby, though it is not yet under the sensor. This is indicated by thehalf-icon 114A shown to the left of the sensor image 120, representingthe stylet magnetic assembly being positioned to the right of the TLSsensor 50 from the perspective of the patient.

In FIG. 8C, the magnetic assembly proximate the stylet distal end 100Bhas advanced under the TLS sensor 50 such that its position andorientation relative thereto is detected by the TLS sensor. This isindicated by the icon 114 on the sensor image 120. Note that the buttonicons 128 provide indications of the actions that can be performed bypressing the corresponding buttons of the console button interface 32.As such, the button icons 128 can change according to which modality thesystem 10 is in, thus providing flexibility of use for the buttoninterface 32. Note further that, as the button pad 82 of the probe 40(FIG. 3A, 3B) includes buttons 84 that mimic several of the buttons ofthe button interface 32, the button icons 128 on the display 30 providea guide to the clinician for controlling the system 10 with the probebuttons 84 while remaining in the sterile field. For instance, if theclinician has need to leave TLS mode and return to US (ultrasound) mode,the appropriate control button 84 on the probe button pad 82 can bedepressed, and the US mode can be immediately called up, with thedisplay 30 refreshing to accommodate the visual information needed forUS functionality, such as that shown in FIG. 4. This is accomplishedwithout a need for the clinician to reach out of the sterile field.

Reference is now made to FIGS. 9 and 10 in describing the integratedcatheter placement system 10 according to another example embodiment. Asbefore, the integrated system 10 includes the console 20, display 30,probe 40 for US functionality, and the TLS sensor 50 for tip locationfunctionality as described above. Note that the system 10 depicted inFIGS. 9 and 10 is similar in many respects to the system shown in FIGS.1 and 2. As such, only selected differences will be discussed below. Thesystem 10 of FIGS. 9 and 10 includes additional functionality whereindetermination of the proximity of the catheter distal tip 76A relativeto a sino-atrial (“SA”) or other electrical impulse-emitting node of theheart of the patient 70 can be determined, thus providing enhancedability to accurately place the catheter distal tip in a desiredlocation proximate the node. Also referred to herein as “ECG” or“ECG-based tip confirmation,” this third modality of the system 10enables detection of ECG signals from the SA node in order to place thecatheter distal tip in a desired location within the patientvasculature. Note that the US, TLS, and ECG modalities are seamlesslycombined in the present system 10, but can be employed in concert orindividually to assist in catheter placement. In one embodiment, it isunderstood that the ECG modality as described herein can be included ina stand-alone system without the inclusion of the US and TLS modalities.Thus, the environments in which the embodiments herein are described areunderstood as merely example environments and are not consideredlimiting of the present disclosure.

FIGS. 9 and 10 show the addition to the system 10 of a stylet 130configured in accordance with the present embodiment. As an overview,the catheter stylet 130 is removably predisposed within the lumen of thecatheter 72 being inserted into the patient 70 via the insertion site73. The stylet 130, in addition to including a magnetic assembly for themagnetically-based TLS modality, includes a sensing component, i.e., anECG sensor assembly, proximate its distal end and including a portionthat is co-terminal with the distal end of the catheter tip for sensingECG signals produced by the SA node. In contrast to the previousembodiment, the stylet 130 includes a tether 134 extending from itsproximal end that operably connects to the TLS sensor 50. As will bedescribed in further detail, the stylet tether 134 permits ECG signalsdetected by the ECG sensor assembly included on a distal portion of thestylet 130 to be conveyed to the TLS sensor 50 during confirmation ofthe catheter tip location as part of the ECG signal-based tipconfirmation modality. Reference and ground ECG lead/electrode pairs 158attach to the body of the body of the patient 70 and are operablyattached to the TLS sensor 50 to enable the system to filter out highlevel electrical activity unrelated to the electrical activity of the SAnode of the heart, thus enabling the ECG-based tip confirmationfunctionality. Together with the reference and ground signals receivedfrom the ECG lead/electrode pairs 158 placed on the patient's skin, theECG signals sensed by the stylet ECG sensor assembly are received by theTLS sensor 50 positioned on the patient's chest (FIG. 10) or otherdesignated component of the system 10. The TLS sensor 50 and/or consoleprocessor 22 can process the ECG signal data to produce anelectrocardiogram waveform on the display 30, as will be described. Inthe case where the TLS sensor 50 processes the ECG signal data, aprocessor is included therein to perform the intended functionality. Ifthe console 20 processes the ECG signal data, the processor 22,controller 24, or other processor can be utilized in the console toprocess the data.

Thus, as it is advanced through the patient vasculature, the catheter 72equipped with the stylet 130 as described above can advance under theTLS sensor 50, which is positioned on the chest of the patient as shownin FIG. 10. This enables the TLS sensor 50 to detect the position of themagnetic assembly of the stylet 130, which is substantially co-terminalwith the distal tip 76A of the catheter as located within the patient'svasculature. The detection by the TLS sensor 50 of the stylet magneticassembly is depicted on the display 30 during ECG mode. The display 30further depicts during ECG mode an ECG electrocardiogram waveformproduced as a result of patient heart's electrical activity as detectedby the ECG sensor assembly of the stylet 130. In greater detail, the ECGelectrical activity of the SA node, including the P-wave of thewaveform, is detected by the ECG sensor assembly of the stylet(described below) and forwarded to the TLS sensor 50 and console 20. TheECG electrical activity is then processed for depiction on the display30. A clinician placing the catheter can then observe the ECG data todetermine optimum placement of the distal tip 76A of the catheter 72,such as proximate the SA node in one embodiment. In one embodiment, theconsole 20 includes the electronic components, such as the processor 22(FIG. 9), necessary to receive and process the signals detected by thestylet ECG sensor assembly. In another embodiment, the TLS sensor 50 caninclude the necessary electronic components processing the ECG signals.

As already discussed, the display 30 is used to display information tothe clinician during the catheter placement procedure. The content ofthe display 30 changes according to which mode the catheter placementsystem is in: US, TLS, or ECG. Any of the three modes can be immediatelycalled up to the display 30 by the clinician, and in some casesinformation from multiple modes, such as TLS and ECG, may be displayedsimultaneously. In one embodiment, as before, the mode the system is inmay be controlled by the control buttons 84 included on the handheldprobe 40, thus eliminating the need for the clinician to reach out ofthe sterile field (such as touching the button interface 32 of theconsole 20) to change modes. Thus, in the present embodiment the probe40 is employed to also control some or all ECG-related functionality ofthe system 10. Note that the button interface 32 or other inputconfigurations can also be used to control system functionality. Also,in addition to the visual display 30, aural information, such as beeps,tones, etc., can also be employed by the system to assist the clinicianduring catheter placement.

Reference is now made to FIGS. 11-12E in describing various details ofone embodiment of the stylet 130 that is removably loaded into thecatheter 72 and employed during insertion to position the distal tip 76Aof the catheter in a desired location within the patient vasculature. Asshown, the stylet 130 as removed from the catheter defines a proximalend 130A and a distal end 130B. A connector 132 is included at theproximal stylet end 130A, and a tether 134 extends distally from theconnector and attaches to a handle 136. A core wire 138 extends distallyfrom the handle 136. The stylet 130 is pre-loaded within a lumen of thecatheter 72 in one embodiment such that the distal end 130B issubstantially flush, or co-terminal, with the catheter opening at thedistal end 76A thereof (FIG. 10), and such that a proximal portion ofthe core wire 138, the handle 136, and the tether 134 extend proximallyfrom a selected one of the extension tubes 74B. Note that, thoughdescribed herein as a stylet, in other embodiments a guidewire or othercatheter guiding apparatus could include the principles of theembodiment described herein.

The core wire 138 defines an elongate shape and is composed of asuitable stylet material including stainless steel or a memory materialsuch as, in one embodiment, a nickel and titanium-containing alloycommonly known by the acronym “nitinol.” Though not shown here,manufacture of the core wire 138 from nitinol in one embodiment enablesthe portion of the core wire corresponding to a distal segment of thestylet to have a pre-shaped bent configuration so as to urge the distalportion of the catheter 72 into a similar bent configuration. In otherembodiments, the core wire includes no pre-shaping. Further, the nitinolconstruction lends torqueability to the core wire 138 to enable a distalsegment of the stylet 130 to be manipulated while disposed within thelumen of the catheter 72, which in turn enables the distal portion ofthe catheter to be navigated through the vasculature during catheterinsertion.

The handle 136 is provided to enable insertion/removal of the styletfrom the catheter 72. In embodiments where the stylet core wire 138 istorqueable, the handle 136 further enables the core wire to be rotatedwithin the lumen of the catheter 72, to assist in navigating thecatheter distal portion through the vasculature of the patient 70.

The handle 136 attaches to a distal end of the tether 134. In thepresent embodiment, the tether 134 is a flexible, shielded cable housingone or more conductive wires electrically connected both to the corewire 138, which acts as the ECG sensor assembly referred to above, andthe tether connector 132. As such, the tether 134 provides a conductivepathway from the distal portion of the core wire 138 through to thetether connector 132 at proximal end 130A of the stylet 130. As will beexplained, the tether connector 132 is configured for operableconnection to the TLS sensor 50 on the patient's chest for assisting innavigation of the catheter distal tip 76A to a desired location withinthe patient vasculature.

As seen in FIGS. 12B-12D, a distal portion of the core wire 138 isgradually tapered, or reduced in diameter, distally from a junctionpoint 142. A sleeve 140 is slid over the reduced-diameter core wireportion. Though of relatively greater diameter here, the sleeve inanother embodiment can be sized to substantially match the diameter ofthe proximal portion of the stylet core wire. The stylet 130 furtherincludes a magnetic assembly disposed proximate the distal end 130Bthereof for use during TLS mode. The magnetic assembly in theillustrated embodiment includes a plurality of magnetic elements 144interposed between an outer surface of the reduced-diameter core wire138 and an inner surface of the sleeve 140 proximate the stylet distalend 130B. In the present embodiment, the magnetic elements 144 include20 ferromagnetic magnets of a solid cylindrical shape stacked end-to-endin a manner similar to the stylet 100 of FIG. 2. In other embodiments,however, the magnetic element(s) may vary from this design in not onlyshape, but also composition, number, size, magnetic type, and positionin the stylet. For example, in one embodiment the plurality of magnetsof the magnetic assembly is replaced with an electromagnetic coil thatproduces a magnetic field for detection by the TLS sensor. These andother variations are therefore contemplated by embodiments of thepresent invention.

The magnetic elements 144 are employed in the stylet 130 distal portionto enable the position of the stylet distal end 130B to be observablerelative to the TLS sensor 50 placed on the patient's chest. As has beenmentioned, the TLS sensor 50 is configured to detect the magnetic fieldof the magnetic elements 144 as the stylet advances with the catheter 72through the patient vasculature. In this way, a clinician placing thecatheter 72 is able to generally determine the location of the catheterdistal end 76A within the patient vasculature and detect when cathetermalposition is occurring, such as advancement of the catheter along anundesired vein, for instance.

The stylet 130 further includes the afore-mentioned ECG sensor assembly,according to one embodiment. The ECG sensor assembly enables the stylet130, disposed in a lumen of the catheter 72 during insertion, to beemployed in detecting an intra-atrial ECG signal produced by an SA orother node of the patient's heart, thereby allowing for navigation ofthe distal tip 76A of the catheter 72 to a predetermined location withinthe vasculature proximate the patient's heart. Thus, the ECG sensorassembly serves as an aide in confirming proper placement of thecatheter distal tip 76A.

In the embodiment illustrated in FIGS. 11-12E, the ECG sensor assemblyincludes a distal portion of the core wire 138 disposed proximate thestylet distal end 130B. The core wire 138, being electricallyconductive, enables ECG signals to be detected by the distal end thereofand transmitted proximally along the core wire. A conductive material146, such as a conductive epoxy, fills a distal portion of the sleeve140 adjacent the distal termination of the core wire 138 so as to be inconductive communication with the distal end of the core wire. This inturn increases the conductive surface of the distal end 130B of thestylet 130 so as to improve its ability to detect ECG signals.

Before catheter placement, the stylet 130 is loaded into a lumen of thecatheter 72. Note that the stylet 130 can come preloaded in the catheterlumen from the manufacturer, or loaded into the catheter by theclinician prior to catheter insertion. The stylet 130 is disposed withinthe catheter lumen such that the distal end 130B of the stylet 130 issubstantially co-terminal with the distal tip 76A of the catheter 72,thus placing the distal tips of both the stylet and the catheter insubstantial alignment with one another. The co-terminality of thecatheter 72 and stylet 130 enables the magnetic assembly to functionwith the TLS sensor 50 in TLS mode to track the position of the catheterdistal tip 76A as it advances within the patient vasculature, as hasbeen described. Note, however, that for the tip confirmationfunctionality of the system 10, the distal end 130B of the stylet 130need not be co-terminal with the catheter distal end 76A. Rather, allthat is required is that a conductive path between the vasculature andthe ECG sensor assembly, in this case the core wire 138, be establishedsuch that electrical impulses of the SA node or other node of thepatient's heart can be detected. This conductive path in one embodimentcan include various components including saline solution, blood, etc.

In one embodiment, once the catheter 72 has been introduced into thepatient vasculature via the insertion site 73 (FIG. 10) the TLS mode ofthe system 10 can be employed as already described to advance thecatheter distal tip 76A toward its intended destination proximate the SAnode. Upon approaching the region of the heart, the system 10 can beswitched to ECG mode to enable ECG signals emitted by the SA node to bedetected. As the stylet-loaded catheter is advanced toward the patient'sheart, the electrically conductive ECG sensor assembly, including thedistal end of the core wire 138 and the conductive material 146, beginsto detect the electrical impulses produced by the SA node. As such, theECG sensor assembly serves as an electrode for detecting the ECGsignals. The elongate core wire 138 proximal to the core wire distal endserves as a conductive pathway to convey the electrical impulsesproduced by the SA node and received by the ECG sensor assembly to thetether 134.

The tether 134 conveys the ECG signals to the TLS sensor 50 temporarilyplaced on the patient's chest. The tether 134 is operably connected tothe TLS sensor 50 via the tether connector 132 or other suitable director indirect connective configuration. As described, the ECG signal canthen be processed and depicted on the system display 30 (FIG. 9, 10).Monitoring of the ECG signal received by the TLS sensor 50 and displayedby the display 30 enables a clinician to observe and analyze changes inthe signal as the catheter distal tip 76A advances toward the SA node.When the received ECG signal matches a desired profile, the cliniciancan determine that the catheter distal tip 76A has reached a desiredposition with respect to the SA node. As mentioned, in one embodimentthis desired position lies within the lower one-third (⅓rd) portion ofthe SVC.

The ECG sensor assembly and magnetic assembly can work in concert inassisting a clinician in placing a catheter within the vasculature.Generally, the magnetic assembly of the stylet 130 assists the clinicianin generally navigating the vasculature from initial catheter insertionso as to place the distal end 76A of the catheter 72 in the generalregion of the patient's heart. The ECG sensor assembly can then beemployed to guide the catheter distal end 76A to the desired locationwithin the SVC by enabling the clinician to observe changes in the ECGsignals produced by the heart as the stylet ECG sensor assemblyapproaches the SA node. Again, once a suitable ECG signal profile isobserved, the clinician can determine that the distal ends of both thestylet 130 and the catheter 72 have arrived at the desired location withrespect to the patient's heart. Once it has been positioned as desired,the catheter 72 may be secured in place and the stylet 130 removed fromthe catheter lumen. It is noted here that the stylet may include one ofa variety of configurations in addition to what is explicitly describedherein. In one embodiment, the stylet can attach directly to the consoleinstead of an indirect attachment via the TLS sensor. In anotherembodiment, the structure of the stylet 130 that enables its TLS andECG-related functionalities can be integrated into the catheterstructure itself. For instance, the magnetic assembly and/or ECG sensorassembly can, in one embodiment, be incorporated into the wall of thecatheter.

FIGS. 13A-15 describe various details relating to the passage of ECGsignal data from the stylet tether 134 to the TLS sensor 50 positionedon the patient's chest, according the present embodiment. In particular,this embodiment is concerned with passage of ECG signal data from asterile field surrounding the catheter 72 and insertion site 73, whichincludes the stylet 130 and tether 134, and a non-sterile field, such asthe patient's chest on which the TLS sensor is positioned. Such passageshould not disrupt the sterile field so that the sterility thereof iscompromised. A sterile drape that is positioned over the patient 70during the catheter insertion procedure defines the majority of thesterile field: areas above the drape are sterile, while areas below(excluding the insertion site and immediately surrounding region) arenon-sterile. As will be seen, the discussion below includes at least afirst communication node associated with the stylet 130, and a secondcommunication node associated with the TLS sensor 50 that operablyconnect with one another to enable ECG signal data transfertherebetween.

One embodiment addressing the passage of ECG signal data from thesterile field to the non-sterile field without compromising thesterility of the former is depicted in FIGS. 13A-15, which depict a“through-drape” implementation also referred to as a “shark fin”implementation. In particular, FIG. 14A shows the TLS sensor 50 asdescribed above for placement on the chest of the patient during acatheter insertion procedure. The TLS sensor 50 includes on a topsurface thereof a connector base 152 defining a channel 152A in whichare disposed three electrical base contacts 154. A fin connector 156,also shown in FIGS. 13A-13D, is sized to be slidingly received by thechannel 152A of the connector base 152, as shown in FIGS. 14B and 15.Two ECG lead/electrode pairs 158 extend from the fin connector 156 forplacement on the shoulder and torso or other suitable external locationson the patient body. The drape-piercing tether connector 132 isconfigured to slidingly mate with a portion of the fin connector 156, aswill be described further below, to complete a conductive pathway fromthe stylet 120, through the sterile field to the TLS sensor 50.

FIGS. 13A-13D show further aspects of the fin connector 156. Inparticular, the fin connector 156 defines a lower barrel portion 160that is sized to be received in the channel 152A of the connector base152 (FIGS. 14B, 15). A hole 162 surrounded by a centering cone 164 isincluded on a back end of an upper barrel portion 166. The upper barrelportion 166 is sized to receive the tether connector 132 of the stylet130 (FIGS. 14C, 15) such that a pin contact 170 extending into a channel172 of the tether connector 132 (FIG. 15) is guided by the centeringhole until it seats within the hole 162 of the fin connector 156, thusinterconnecting the tether connector with the fin connector. Anengagement feature, such as the engagement feature 169 shown in FIGS.13C and 13D, can be included on either side of the fin connector 156 toengage with corresponding detents 173 (FIG. 13F) on the tether connector132 to assist with maintaining a mating between the two components. Ifdisengagement between the two components is desired, a sufficientreverse pull force is applied to the tether connector 132 while holdingor securing the fin connector 156 to prevent its removal from thechannel 152A of the connector base 152.

FIG. 13D shows that the fin connector 156 includes a plurality ofelectrical contacts 168. In the present embodiment, three contacts 168are included: the two forward-most contact each electrically connectingwith a terminal end of one of the ECG leads 158, and the rear contactextending into axial proximity of the hole 162 so as to electricallyconnect with the pin contact 170 of the tether connector 132 when thelatter is mated with the fin connector 156 (FIG. 15). A bottom portionof each contact 168 of the fin connector 156 is positioned toelectrically connect with a corresponding one of the base contacts 154of the TLS sensor connector base 152. In one embodiment, the bottomportion of each contact 168 includes a retention feature, such as anindentation 168A. So configured, each contact 168 can resiliently engagea respective one of the base contacts 154 when the fin connector 156 isreceived by the TLS sensor connector base 152 such that a tip of eachbase contact is received in the respective indentation 168A. Thisconfiguration provides an additional securement (FIG. 15) to assist inpreventing premature separation of the fin connector 156 from theconnector base 152. Note that many different retention features betweenthe base contacts 154 and the fin contacts 168 can be included inaddition to what is shown and described herein.

FIGS. 13E and 13F depict various details of the tether connector 132according to one embodiment, including the tether connector channel 172,the pin contact 170 disposed in the channel, and detents 173 forremovably engaging the engagement features 169 of the fin connector 156(FIGS. 13A-13D), as described above. FIG. 13E further shows a pluralityof gripping features 171 as an example of structure that can be includedto assist the clinician in grasping the tether connector 132.

FIG. 14B shows a first connection stage for interconnecting the abovedescribed components, wherein the fin connector 156 is removably matedwith the TLS sensor connector base 152 by the sliding engagement of thelower barrel portion 160 of the fin connector with the connector basechannel 152A. This engagement electrically connects the connector basecontacts 154 with the corresponding fin contacts 168 (FIG. 15).

FIG. 14C shows a second connection stage, wherein the tether connector132 is removably mated with the fin connector 156 by the slidingengagement of the tether connector channel 172 with the upper barrelportion 166 of the fin connector. This engagement electrically connectsthe tether connector pin contact 170 with the back contact 168 of thefin connector 156, as best seen in FIG. 15. In the present embodiment,the horizontal sliding movement of the tether connector 132 with respectto the fin connector 156 is in the same engagement direction as when thefin connector is slidably mated to the sensor connector base channel152A (FIG. 14B). In one embodiment, one or both of the stylet 130/tetherconnector 132 and the fin connector 156 are disposable. Also, the tetherconnector in one embodiment can be mated to the fin connector after thefin connector has been mated to the TLS sensor, while in anotherembodiment the tether connector can be first mated to the fin connectorthrough the surgical drape before the fin connector is mated to the TLSsensor.

In the connection scheme shown in FIG. 14C, the stylet 130 is operablyconnected to the TLS sensor 50 via the tether connector 132, thusenabling the ECG sensor assembly of the stylet to communicate ECGsignals to the TLS sensor. In addition, the ECG lead/electrode pairs 158are operably connected to the TLS sensor 50. In one embodiment,therefore, the tether connector 132 is referred to as a firstcommunication node for the stylet 130, while the fin connector 156 isreferred to as a second communication node for the TLS sensor 50. Aswill be seen, various other first and second communication nodes can beemployed to enable the establishment of a conductive pathway between theECG sensor assembly and the TLS sensor or other system component.

Note that various other connective schemes and structures can beemployed to establish operable communication between the stylet and theTLS sensor. For instance, the tether connector can use a slicing contactinstead of a pin contact to pierce the drape. Or, the fin connector canbe integrally formed with the TLS sensor. These and other configurationsare therefore embraced within the scope of embodiments of the presentdisclosure.

As mentioned, a drape 174 is often placed over the patient 70 andemployed as a barrier to separate a sterile field of the patient, e.g.,areas and components above the drape and proximate to the insertion site73 (including the catheter 72, the stylet 130, and tether 134 (FIG. 10))from non-sterile areas outside of the sterile field, e.g., areas andcomponents below the drape, including the patient's chest, the sensor 50(FIG. 10) placed on the chest, and regions immediately surrounding thepatient 70, also referred to herein as a non-sterile field. As seen inFIG. 15, the sterile drape 174 used during catheter placement toestablish the sterile field is interposed between the interconnection ofthe tether connector 132 with the fin connector 156. As just described,the tether connector 132 includes the pin contact 170 that is configuredto pierce the drape 174 when the two components are mated. This piercingforms a small hole, or perforation 175, in the sterile drape 174 that isoccupied by the pin contact 170, thus minimizing the size of the drapeperforation by the pin contact. Moreover, the fit between the tetherconnector 132 and the fin connector 156 is such that the perforation insterile drape made by piercing of the pin contact 170 is enclosed by thetether connector channel 172, thus preserving the sterility of the drapeand preventing a breach in the drape that could compromise the sterilebarrier established thereby. The tether connector channel 172 is shapedand configured so as to fold the sterile drape 174 down prior topiercing by the pin contact 170 such that the pin contact does notpierce the drape until it is disposed proximate the hole 162 of the finconnector 156 and such that the drape does not bunch up within thechannel. It is noted here that the tether connector 132 and finconnector 156 are configured so as to facilitate alignment therebetweenblindly through the opaque sterile drape 174, i.e., via palpation absentvisualization by the clinician of both components.

As already mentioned, note further that the fin contacts 168 of the finconnector 156 as shown in FIG. 15 include the indentations 168A, whichare configured to mate with the sensor base contacts 154 in such a wayas to assist in retaining the fin connector in engagement with thesensor base channel 152A. This in turn reduces the need for additionalapparatus to secure the fin connector 156 to the TLS sensor 50. In otherembodiments, retention features that are separate from the electricalcontacts can be employed to assist in retaining the fin connector inengagement with the sensor base channel. In one embodiment, the basecontacts 154 can be configured as pogo pins such that they arevertically displaceable to assist in retaining the fin connector 156.

FIG. 16 shows a typical ECG waveform 176 of a patient, including aP-wave and a QRS complex. Generally, and with respect to the presentsystem 10, the amplitude of the P-wave varies as a function of distanceof the ECG sensor assembly from the SA node, which produces the P-waveof the waveform 176. A clinician can use this relationship indetermining when the catheter tip is properly positioned proximate theheart. For instance, in one implementation the catheter tip is desirablyplaced within the lower one-third (⅓rd) of the superior vena cava, ashas been discussed. The ECG data detected by the ECG sensor assembly ofthe stylet 130 is used to reproduce waveforms such as the waveform 176,for depiction on the display 30 of the system 10 during ECG mode.

Reference is now made to FIG. 17 in describing display aspects of ECGsignal data on the display 30 when the system 10 is in ECG mode, thethird modality described further above, according to one embodiment. Thescreenshot 178 of the display 30 includes elements of the TLS modality,including a representative image 120 of the TLS sensor 50, with the icon114 corresponding to the position of the distal end of the stylet 130during transit through the patient vasculature. The screenshot 178further includes a window 180 in which the current ECG waveform capturedby the ECG sensor assembly of the stylet 130 and processed by the system10 is displayed. The window 180 is continually refreshed as newwaveforms are detected.

Window 182 includes a successive depiction of the most recent detectedECG waveforms, and includes a refresh bar 182A, which moves laterally torefresh the waveforms as they are detected. Window 184A is used todisplay a baseline ECG waveform, captured before the ECG sensor assemblyis brought into proximity with the SA node, for comparison purposes toassist the clinician in determining when the desired catheter tiplocation has been achieved. Windows 184B and 184C can be filled byuser-selected detected ECG waveforms when the user pushes apredetermined button on the probe 40 or the console button interface 32.The waveforms in the windows 184B and 184C remain until overwritten bynew waveforms as a result of user selection via button pushes or otherinput. As in previous modes, the depth scale 124, status/action indicia126, and button icons 128 are included on the display 30. An integrityindicator 186 is also included on the display 30 to give an indicationof whether the ECG lead/electrode pairs 158 are operably connected tothe TLS sensor 50 and the patient 70.

As seen above, therefore, the display 30 depicts in one embodimentelements of both the TLS and ECG modalities simultaneously on a singlescreen, thus offering the clinician ample data to assist in placing thecatheter distal tip in a desired position. Note further that in oneembodiment a printout of the screenshot or selected ECG or TLS data canbe saved, printed, or otherwise preserved by the system 10 to enabledocumentation of proper catheter placement.

Although the embodiments described herein relate to a particularconfiguration of a catheter, such as a PICC or CVC, such embodiments aremerely exemplary. Accordingly, the principles of the present inventioncan be extended to catheters of many different configurations anddesigns.

FIGS. 18-19B depict examples of contact engagement configurations forthe tether connector 132 and fin connector 156. Specifically, FIG. 18depicts the fin contacts 168 of the fin connector 156 according to oneembodiment, wherein the rear contact includes a spring clipconfiguration 168B for receiving the pin contact 170 (FIG. 15) of thetether connector 132 via the centering cone 164 or other aperturedefined in the fin connector. FIGS. 19A and 19B depict an engagementscheme according to another embodiment, wherein the pin contact 170 ofthe tether connector 132 includes a barbed feature 170A that, wheninserted into the centering cone 164 or other aperture of the finconnector 156, engages a shoulder 168C defined on the rear fin contact168 of the fin connector so as to help prevent premature removal of thepin contact from the fin connector. These embodiments thus serve asnon-limiting examples of a variety of contact configurations that can beincluded with the fin connector 156, the sensor connector base 152, andthe tether connector 132. Note that unless referred to as otherwise, thecontacts described herein are understood to include electrical contactsused in establishing a conductive pathway.

The embodiments to be described below in connection with FIGS. 20A-32each depict an example connection scheme as a means for establishing aconductive or other communication pathway between a patient's sterilefield and a non-sterile field, i.e., areas outside of the sterile field.Thus, the embodiments described herein serve as examples of structure,material, and/or compositions corresponding to the means forestablishing a conductive or other communication pathway. In particular,various embodiments described herein disclose examples for breaching orotherwise circumventing a sterile barrier separating the sterile fieldfrom the non-sterile field so as to provide at least a portion of theconductive pathway for the passage of ECG signals from a sensingcomponent such as the ECG sensor assembly of the stylet 130 to thesensor 50, also referred to herein as a TLS sensor or chest sensor, orother suitable data-receiving component of the system 10. Note thatthese embodiments are merely examples of a variety of means forestablishing such a conductive or other communication pathway, and arenot to be considered limiting of the scope of the present disclosure. Itis therefore appreciated that the means for establishing a conductive orother communication pathway can be employed for transferring ECG signalsor other information, electrical signals, optical signals, etc.

As will be seen, many of the embodiments to be described include atether connector, also referred to herein as a first communication node,which is operably connected to the stylet 130 and included in thesterile field, the tether connector is configured to operably attach toa connector included on the sensor 50 or other suitable component of thesystem 10, also referred to herein as a second communications node,which is disposed outside of the sterile field. Note, however, that thefirst communication node and second communication node are contemplatedas generally referring to various connector interfaces that provide aconductive pathway from the sterile field to the non-sterile field toenable the passage of ECG signals as described above. It is appreciatedthat the conductive pathway is a communication pathway and includes anelectrical pathway, an optical pathway, etc. Further, the communicationnode connection schemes described and contemplated herein can beemployed with systems involving the use of modalities exclusive of ECGsignals for navigation or placement of a catheter or other medicaldevice.

Note further that the embodiments to follow that describe configurationsfor breaching a drape or other non-transparent sterile barrier areconfigured such that location of a communication node disposedout-of-sight under the drape/barrier is facilitated by palpation of theclinician, thus easing location and connection of the first and secondcommunication nodes. Also, many of the connector configurationsdescribed herein can be configured as one-use, disposable components soas to minimize concerns with infection.

Reference is now made to FIGS. 20A-20C, which depict a connection schemeas a means for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. In particular, FIGS.20A-20C depict a tether connector 232 that includes an outer housing 234and a blade holder 236 that attaches to the outer housing. A bladecontact 238 is secured by the blade holder 236 such that the bladecontact extends into a channel 240 of the tether connector. The bladecontact 238 serves to create a slice perforation in a drape that isinterposed between the tether connector and the fin connector 256 whenthe tether connector 232 is slid on to engage the fin connector in themanner described in previous embodiments. As before, the outer housing234 of the tether connector envelops and protects the perforation so asto prevent contamination and compromise of the sterile field.

FIG. 20C shows that a fin connector 256 includes a fin contact 268 thatis configured to physically interconnect with the blade contact 238 whenthe tether connector is slid on to the fin connector 256, thusestablishing a conductive pathway through the sheath so as to enable ECGsignals from an ECG sensing component, i.e., the ECG sensor assemblydescribed above for instance, to pass to the sensor 50 via the bladecontact 238/fin contact 268 engagement. Note that the particularconfiguration of the blade and fin contacts can be varied from what isdescribed herein. For instance, the tether connector can include two ormore blades or contacts for engagement with corresponding fin contactsto enable multiple conductive pathways to be established, if desired.The engagement surfaces of the tether connector and the fin connectorcan also vary from what is shown and described. In one embodiment, alight source can be included with the fin connector or other connectorsas described herein so as to provide illumination through the drape 174and provide visual assistance in locating the fin connector forinterconnection with the tether connector.

As seen in FIGS. 14A and 14B, in one embodiment the ECG leads 158 arepermanently connected to the fin connector 156. FIG. 21A depicts anotherpossible embodiment, wherein the ECG leads are removably attached to thefin connector 156 via a connector, such as a horseshoe connector 270,best seen in FIG. 21B. FIG. 21A further shows that the fin connector 156is permanently attached to the sensor 50. These and other variations inthe connective schemes of the various components of the system 10 aretherefore contemplated as falling within the scope of the presentdisclosure. In another embodiment, the electrode of each lead isremovably attachable from the lead, such as via a snap connection, forinstance.

Reference is now made to FIGS. 22A-22C, which depict a connection schemeas a means for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. In particular, FIGS.22A-22C depict a tether connector 332 that includes a channel 372 forslidably engaging an upper barrel 166 of a fin connector 356 disposed onthe sensor 50, in a manner similar to previous embodiments. The tetherconnector 332 includes a bi-positional top cap 374 to which is attacheda pin contact 370 or other piercing contact.

The top cap 374 is positioned in an un-actuated first position, shown inphantom in FIG. 22B, when the tether connector 332 is first slid on tothe fin connector 356. The drape, removed for clarity, is interposedbetween the upper barrel 166 of the fin connector 356 and the tetherconnector channel 372, similar to earlier embodiments. After the tetherconnector 332 is positioned on the fin connector 356, the top cap 374can then be depressed by the clinician into an actuated second positionshown in FIG. 22B, wherein the pin contact 370 is pressed downwardthrough the drape and into operable engagement with a correspondingcontact disposed in the fin connector 356. The tether connector 332 isthus positioned as shown in FIG. 22C. In addition to establishing aconductive path through the drape 174, this engagement of the pincontact 370 locks the tether connector 332 on to the fin connector 356so as to prevent premature separation of the components.

Reference is now made to FIGS. 23A and 23B, which depict a connectionscheme as a means for establishing a conductive pathway between sterileand non-sterile fields, according to one embodiment. In particular, FIG.23A depicts a tether connector 432 including a pin contact 440 or othersuitable contact attached to an actuation assembly 442. The actuationassembly 442 includes lever arms for selectively lowering the pincontact 440 through an opening defined by a male end 448 of a housing446 in which the actuation assembly is disposed. The male end 448 of thehousing is configured to be received by a sensor connector receptacle450 disposed on the sensor 50 or other suitable component of the system,such as a remote module operably connected to the sensor, for instance.

To interconnect the tether connector 432 to the sensor connectorreceptacle 450, the male end 448 of the tether connector 432 is brought,above the drape 174, into proximity with the receptacle 450. Theactuation assembly 442 is then actuated by raising the lever arms 444,as shown in FIG. 23B. The pin contact 440 is forced downward through thedrape 174, thus defining a perforation therein. The male end 448 canthen be fully received into the sensor receptacle 450, wherein the pincontact 440 operably connects with a suitable contact of the sensorconnector receptacle. The connector scheme shown in FIGS. 23A and 23B isuseful for imposing a minimal downward force on the body of the patientduring connector interconnection. Further, the actuation assembly 442provides a predetermined force in connecting the first communicationnode (the tether connector 432) with the second communication node (thesensor connector receptacle 450), and thus does not rely on aclinician's estimation of force to establish the node connection. Inanother embodiment, the housing 446 and the sensor receptacle 450 can bealigned and mated before the actuation assembly 442 is actuated topierce the contact 440 through the drape.

Reference is now made to FIG. 24, which depicts a connection scheme as ameans for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. As in the embodimentshown in FIGS. 23A and 23B, the present interconnection scheme minimizesdownward pressure on the body of the patient during interconnection ofthe nodes. As shown, a tether connector 532 includes a pin contact 540or other suitable contact included with a threaded cap 542, whichdefines threads on an inside surface thereof. The threaded cap 542 isconfigured to threadingly receive a threaded base 544 disposed on thesensor 50 or other suitable component of the system, such as a remotemodule operably connected to the sensor, for instance. As before, thedrape 174 is interposed therebetween.

To interconnect the tether connector 532 to the sensor 50, the threadedcap 542 of the tether connector is brought, above the drape 174, intoproximity with the threaded base 544 and threaded on to the base. Thiscauses the pin contact 540 to penetrate the drape 174, thus defining aperforation therein. Further threading of the cap 542 on to the base 544causes the pin contact 540 to engage a contact receptacle 546 includedin the base 544, thus operably interconnecting the two nodes. In oneembodiment, the tether 134 is rotatably attached to the threaded cap 542so as to prevent twisting of the tether during threading. The connectorscheme shown in FIG. 24 is useful for imposing a minimal downward forceon the body of the patient during connector interconnection as the forceto join the two connectors is directed laterally with respect to thepatient via the threading operation. Note further that a variety ofthread configurations and locations, as well as different cap and baseconfigurations, are contemplated by the present disclosure.

Reference is now made to FIGS. 25A and 25B, which depict a connectionscheme as a means for establishing a conductive pathway between sterileand non-sterile fields, according to one embodiment. As in the previousembodiment, the present interconnection scheme minimizes downwardpressure on the body of the patient during interconnection of the nodes.As depicted in FIGS. 25A and 25B, a tether connector 632 includes one ormore piercing contacts, such as pin contacts 640A and 640B that arerespectively included on slide arms 642A and 642B. One or more contactreceptacles, such as contact receptacles 644A and 644B, are included ona portion of the sensor 50, such as a sensor fin 646, or other suitablesystem component. As before, the drape 174 is interposed between thetether connector 632 and the sensor fin 646 to serve as a sterilebarrier.

To interconnect the tether connector 632 to the sensor fin 646, thetether connector is brought, above the drape 174, into proximity withthe sensor fin such that the slide arms 642A and 642B straddle thesensor fin and such that the pin contacts 640A and 640B are aligned withcorresponding contact receptacles 644A and 644B, as shown in FIG. 25A.The slide arms 642A and 642B are then slid toward one another such thatthe pin contacts 640A and 640B penetrate the drape 174, each defining aperforation therein. The slide arms 642A and 642B are slid inward untilthe pin contacts 640A and 640B seat within and operably connect with thecorresponding contact receptacles 644A and 644B, as seen in FIG. 25B,thus interconnecting the two nodes. The connector scheme shown in FIGS.25A and 25B is useful for imposing a minimal downward force on the bodyof the patient during connector interconnection as the force to join thetwo connectors is directed laterally with respect to the patient. Notethat the particular configuration of the tether connector, the sensorfin, and the contacts can vary from what is explicitly described herein.For instance, in one embodiment the slide arms can be configured asbi-positional rocker arms that are connected in a see-saw configurationwith respect to one another. Also, one, two, or more contacts can beincluded on the slide arms.

Reference is now made to FIGS. 26A and 26B, which depict a connectionscheme as a means for establishing a conductive pathway between sterileand non-sterile fields, according to one embodiment. As shown, anintegrated connector 730 is incorporated into the drape 174 so as toenable operable interconnection therethrough. In the illustratedembodiment, the integrated connector 730 includes a conductive baseportion 734 from which extend mechanical connectors, such as snap balls736A and 736B.

As shown in FIG. 26B, the integrated connector 730 is positioned in thedrape 174 as to be connectable with both a suitable receptacle 738 of atether connector 732 and a suitable receptacle 740 of the sensor 50 orother suitable component of the system 10. In particular, the tetherconnector 732 can be snap-attached to the integrated connector 730,after which the integrated connector can be attached to the sensor 50,thus providing a suitable pathway for signals from the ECG sensorassembly in the sterile field to be transmitted through the sterilebarrier of the drape 174 to the sensor in the non-sterile field. It isappreciated that, in other embodiments, the integrated connector caninclude other configurations, such as different mechanical connectors,e.g., friction connectors, male/female connectors, etc., and as such thereceptacles on the tether connector and sensor can likewise be modifiedto accommodate the different mechanical connectors. Also, the connectivescheme described above can be reversed such that the receptacles areincluded on the integrated connector and the snap balls on therespective tether connector and sensor. Further, though presentlydepicted as a unitary component, the integrated connector in otherembodiments can include two or more pieces that are attached to eachother through a previously defined hole in the drape during manufacturethereof. These and other variations are therefore contemplated.

Reference is now made to FIG. 27, which depicts a connection scheme as ameans for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. In detail, FIG. 27depicts an intermediate module, i.e., ECG module 750, disposed outsideof the sterile field of the patient, which is operably connected to thesensor 50 of the system 10 via a sensor cable 752. The ECG module 750 isalso operably connected to the ECG leads 158. In one embodiment, the ECGmodule 750 includes the circuitry and other components necessary forreceipt and analysis of the ECG signal detected by the ECG sensorassembly of the stylet 130. As such, a conductive pathway is establishedbetween the stylet 130 and the ECG module 750 by traversing the sterilefield of the patient. In the present embodiment, this is accomplished bya tether connector 762 of the tether 134.

As depicted in FIG. 27, the tether connector 762 operably attaches to areceptacle 764 of the ECG module 750. As shown, the tether connector 762can include a sufficiently long handle that enables the clinician toattach the sterile tether connector to the receptacle 764 of thenon-sterile ECG module 750 without touching the ECG module itself, thuspreventing any compromise of the sterile field. In one embodiment, thehandle of the tether connector 762 can include an extendable J-hookcontact, for instance, that can operably connect to a suitable contactof the ECG module.

FIG. 28 shows another example of a tether connector that can be employedwith the ECG module 750 of FIG. 27 or other suitable component of thesystem 10 as part of a connection scheme as a means for establishing aconductive pathway between sterile and non-sterile fields, according toone embodiment. In particular, FIG. 28 depicts a tether connector 832,which includes a handle and a barbed contact 836 or other suitablecontact at a proximal end thereof. A sterile shield 838 is interposedbetween the handle 834 and the contact 836. The sterile shield 838assists in protecting the hand of the clinician while inserting thecontact 836 into the receptacle 764 of the ECG module 750 in a mannersimilar to what is shown in FIG. 27. Thus, the sterile shield 838 servesas an additional barrier to prevent inadvertent contact by the clinicianwith a component outside of the sterile field, such as the ECG module750. Note that the size, shape, and particular configuration of thesterile shield and/or tether connector can vary from what is explicitlydescribed in the present embodiment.

FIGS. 29A and 29B show yet another example of a connection scheme thatcan be employed with the ECG module 750 of FIG. 27 or other suitablecomponent of the system 10 as a means for establishing a conductivepathway between sterile and non-sterile fields, according to oneembodiment. In particular, FIG. 29A shows that the ECG module 750 can beenveloped by a sterile bag 850. A connector, such as the integratedconnector 730 described above in connection with FIGS. 26A and 26B, canbe incorporated into the bag. As shown in FIG. 29B, an inner snap ballor other mechanical connector of the integrated connector 730 can bereceived by the suitably corresponding receptacle 764 of the ECG module750. The tether connector of the system 10 can then be operablyconnected with the outer snap ball or other connector of the integratedconnector 730, thus establishing a conductive pathway between thesterile field and the non-sterile field without compromising sterility.Note that the sterile bag 850 can include any one or more of a varietyof suitable materials, including plastic. Note also that the integratedconnector can include other connector configurations in addition to whatis explicitly described herein. In one embodiment, the sterile bagincludes no integrated connector, but rather is pierced by a pin contactof the tether connector, such as the barbed contact 836 included on thetether connector 832 of FIG. 28.

Reference is now made to FIG. 30, which depicts a connection scheme as ameans for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. Specifically, thestylet 130 includes a tether connector 862 as a first communicationnode, as in previous embodiments. A remote sensor connector 864 is alsoincluded as a second communications node, and is operably connected tothe sensor 50 of the system 10 via a remote sensor connector cable 866.The tether connector 862 and remote sensor connector 864 operablyconnect to one another along a connection interface 868. The drape 174that serves as a sterile barrier is interposed between the tetherconnector 862 and remote sensor connector 864 at the connectioninterface 868, and a suitable drape piercing configuration is includedwith the tether connector and the remote sensor connector to establish aconductive pathway through the drape. The present embodiment thusdiscloses one embodiment wherein the second communication node islocated remotely with respect to the sensor 50.

Reference is now made to FIG. 31, which depicts a connection scheme as ameans for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. Specifically, thepresent embodiment includes the tether connector 862 and the remotesensor connector 864 that operably connect to one another along theconnection interface 868, as described in connection with FIG. 30,above. The remote sensor connector 864 in the present embodiment isplaced proximate the catheter insertion site 73 in a region over which afenestration 880 defined in the drape 174 (portions of the drape omittedfor clarity) is positioned to enable clinician access to the insertionsite during catheter placement. The remote sensor connector 864 isadhered to the patient's skin proximate the catheter insertion site 73with the use of an adhesive, tape, etc., before the region surroundingthe insertion site is sterilized in preparation for catheter insertion.Thus, when the insertion site is sterilized, the remote sensor connector864 is also sterilized. Later, when connection of the tether connector862 to the remote sensor connector 864 is made, the clinician can handlethe latter component without compromising the sterile field of thepatient. It is appreciated that the particular configurations of thetether connector and the remote sensor connector can vary while stillresiding within the scope of the present embodiment.

Reference is now made to FIG. 32, which depicts a connection scheme as ameans for establishing a conductive pathway between sterile andnon-sterile fields, according to one embodiment. Specifically, FIG. 32shows the probe 40 employed by the system 10 for US functionality, asdescribed above in connection with FIGS. 3A and 3B. A sterile sheath 900is placed over the probe 40 so as to bring the probe into the sterilefield of the patient. A connection interface, such as a receptacle 910,is included on the probe 900 and is configured so as to be operableconnectable with a tether connector 920. In one embodiment, for example,the tether connector 920 includes a pin contact that penetrates thesterile sheath 900 to mate with the receptacle 910 in such a way as toprevent contamination of the sterile field. In this way, the tetherconnector 920, as a first communication node, operably connects with theprobe 40, as a second communications node. In turn, the probe 40 isoperably connected to the system console 20, as seen in FIG. 31 forexample, so as to enable ECG signals received by the ECG sensor assemblyof the stylet 130 via the tether connector 920 to be forwarded to theconsole, the sensor 50, or other system component for processing, asdescribed above. In another embodiment, the receptacle 910 or othersuitable connection interface can be included on the cable connectingthe probe 40 to the system console 20. The particular contactconfiguration of the receptacle 910 and tether connector 920 can bevaried according to the understanding of one skilled in the art. Forinstance, an integrated connector such as that shown in FIGS. 26A and26B can be incorporated into the sterile sheath in one embodiment. Notefurther that, though including plastic in the present embodiment, thesterile sheath as described herein can include other suitable materialsfor providing sterility.

Reference is now made to FIG. 33 in describing means for establishing aconductive pathway between sterile and non-sterile fields, according toone embodiment. As shown, the tether 134 includes a wireless module 950,included within the sterile field, which serves as a first communicationnode for wirelessly transmitting (via RF or other suitable frequency orfrequency range) ECG data received from the ECG sensor assembly of thestylet 130 to a data-receiving component as a second communication node,such as the sensor 50 or other suitable component of the system 10. Awireless module ground electrode 952 is operably connected with thewireless module 950 for placement in the sterile field proximate thecatheter insertion site 73. A system ground electrode 158A extends fromthe sensor 50 for placement outside of the sterile field but proximateboth the catheter insertion site 73 and the location of the wirelessmodule ground electrode 952. One possible placement location for thesystem ground electrode 158A is beneath the patient arm, as depicted inFIG. 33. The system reference electrode 158B is placed on the lowertorso of the patient 70 or other suitable location, as in previousembodiments. Note that the wireless module and system console asdiscussed herein can be configured in one or more of a variety of waysand include components for wireless signal transmission and receptionnot specifically detailed herein, such as patch or other antennas,signal transducers, etc.

With the system configured as shown in FIG. 33, the system groundelectrode 158A can be electrically driven such that it produces avoltage that is sensed by the passive wireless module ground electrode952, given its proximate location with respect to the system groundelectrode. This enables both ground electrodes to be at substantiallyequal electric potentials, thus enabling the wireless module 950 toutilize the wireless module ground electrode 952 and the ECG signalsfrom the ECG sensor assembly of the stylet 130, e.g., the core wire 138(FIGS. 12C-12E) in one embodiment, to detect and wirelessly transmit theECG data to the sensor 50 for comparison with the data sensed by thesystem reference electrode 158B in order to obtain the desired P-wavewaveform (e.g., FIG. 16). The data comparison in one embodiment is adifferential comparison between the ECG data as obtained by the ECGsensor assembly of the stylet 130, the wireless module ground electrode952, and the system reference electrode 158B. In one embodiment, thesystem ground electrode 158A, like the wireless module ground electrode952, can be passive and not electrically driven. Note also that theanalog ECG data can be digitized or otherwise processed by the wirelessmodule 950 before transmission to the sensor 50 or other systemcomponent, such as the console 20.

FIG. 34 describes yet another wireless configuration as a means forestablishing a conductive pathway between sterile and non-sterilefields, according to one embodiment. As shown, a positive electrode 954Aat a location A and a negative electrode 954B at a location B areincluded with the sensor 50 and positioned on the torso of the patient70, while a positive wireless module electrode 956 is included with thewireless node 950, as indicated at location C, positioned on or in thepatient proximate the catheter insertion site 73. The ECG sensorassembly of the stylet 130, e.g., the core wire 138 in one embodiment,serves as a negative electrode for the wireless portion of the depictedconfiguration, indicated at D in FIG. 34 at its final position. Notethat in one embodiment the locations A and B of the electrodes 954A and954B, respectively, can be altered on the patient body to tune thesystem 10 for best ECG signal reception.

In the present embodiment, the electrodes 954A and 954B serve as a firstindependent source for sampling bipolar ECG signals. The ECG data fromthese electrodes are digitized and forwarded to the console 20 or othersuitable system component via the cable interconnecting the sensor 50and the console (path 1) outside of the sterile field. The wirelessmodule electrode 956 and the ECG sensor assembly serve as a secondindependent source for sampling bipolar ECG signals. The ECG data fromthese electrodes are digitized and forwarded wirelessly to the console20 via the wireless module 950 (path 2) within the sterile field. Thus,in the present embodiment the wireless module 950 serves as a firstcommunication node, and a wireless receiver of the console 20 as asecond communication node for the transfer of ECG signals between thetwo nodes. Note that the polarities of the afore-mentioned electrodescan be reversed in other embodiments.

The ECG signals received along both paths 1 and 2 are baseline correctedby appropriate circuitry of the console 20 to adjust for DC offset anddrift. After such correction, a non-changing reference, or baseline,P-wave waveform 176A from path 1 can be produced, as seen in FIG. 35A,for example. Similarly, a P-wave waveform 176B as seen in FIG. 35B isproduced from path 2, which waveform changes as the stylet 130 withinthe catheter 72 is advanced toward the heart of the patient. During suchadvancement, the waveform 176B from path 2 is subtracted from the P-wavewaveform 176A from path 1, employing a digital differential amplifier,for instance. This subtraction removes all common components of thewaveforms represented by each of the signals, and enables the console 20to depict via its display 30 only the differences in the two signals, asseen for example by the waveform 176C shown in FIG. 35C. The change inP-wave of the waveform from path 2 can then be easily observed duringcatheter advancement. Thus the present embodiment enables an easilyobservable digital display of ECG data to be represented whilepreventing a physical breaching of a sterile barrier, such as a surgicaldrape, for the passage of such data.

Note that in other embodiments the wireless module electrode 956 caninclude other configurations, including a conductive element imbeddedinto an introducer sheath, in contact with the bloodstream of thepatient, which is commonly disposed through the insertion site 73 duringcatheter placement. The introducer can include a connector on a proximalportion thereof to enable a connection with the wireless node 950 to bemade, in one embodiment.

Note further that one or more of a variety of wireless protocols can beemployed in transmitting wireless signals in accordance with theembodiments described herein, including one or more of the IEEE 802.11family of specifications, etc. Also note that in one embodiment thewireless module can be included in a sterile sheath, as described inprevious embodiments, to bring the module within the sterile field,together with connectors for operably connecting the wireless moduleelectrode through the sheath or included in the sheath itself. Ofcourse, other methods for maintaining the wireless module within thesterile field can also be employed. In one embodiment, the wirelessmodule can include buttons that further enable control of the system 10from within the sterile field.

FIG. 36 shows that in one embodiment the sensor 50 can be retro-fittedwith a wireless module 960 to enable signals received by the sensor tobe wirelessly transmitted to the console 20 or other suitable componentof the system 10. For instance, ECG data received by the ground andreference electrodes 158A, 158B (FIG. 34) can be received by the sensor50 then wirelessly transmitted to the system console via the wirelessmodule 960. The wireless module 960 can include an antenna or othertransmitting component and can operably connect to the sensor 50 via asensor cable 962 or other suitable interface. Note that the wirelessmodule 960 can be employed in connection with other embodimentsdescribed herein, including those depicted in FIGS. 10 and 33, forinstance.

FIG. 37 shows a retention feature for preventing inadvertent separationof the fin connector 156 from the sensor connector base 152 or otherreceptacle with which the fin connector operably connects, according toone embodiment. As shown, the fin connector 156 includes a retention arm970 that is resiliently attached to the fin connector body. Theretention arm 970 includes a tab 972 that slides over and engages a lip974 included with the connector base 152 of the sensor 50 when the finconnector 156 is slidably received in the sensor channel 152A (FIG.14A). The engagement of the tab 972 with the lip 974 preventsinadvertent removal of the fin connector 156 during use. When removal ofthe fin connector 156 from the sensor connector base 152 is desired, theretention arm 970 is lifted so as to disengage the tab 972 from the lip974, after which the fin connector can be slid our of engagement withthe sensor channel 152A. This configuration can be employed either withor independent of other retention features, such as the indentations168A (FIG. 13D). Note that in other embodiments a variety ofmodifications and configurations can be employed in assisting tomaintain engagement between the fin connector and the connector. Forinstance, the retention arm in one embodiment can be operably attachedto one or more of the fin contacts 168 (FIG. 13D) such thatdisplacement, e.g., lifting laterally moving, pinching, etc., of theretention arm or other suitable fin connector component disengages thefin contact(s) from the base contacts (FIG. 15), thus reducing theoverall retention force provided by the engagement of the fin contactswith the base contacts. Note further that these principles can beapplied to the other connector schemes disclosed or contemplated inaddition to the fin connector described here.

In addition to the above embodiments depicting various connectionschemes as means for establishing a conductive pathway between sterileand non-sterile fields, other configurations can be employed, asappreciated by one skilled in the art, for performing the samefunctionality. Such other configurations can include, for example,wireless transmission of ECG signals from the stylet to the sensor orthe system component, the inclusion of electrically conductive thread inthe drape, the inclusion of an electrically conductive window (e.g.,composed of an electrically conductive plastic or foil) in the steriledrape, etc. In yet another embodiment, a proximal end of thestylet/guidewire itself can be used to pierce the drape for receipt intoa connector on the sensor. In this case, no tether is included on theproximal end of the stylet, and the stylet itself serves as theconductive pathway for transmitting ECG signals from the stylet sensorassembly to the sensor on the patient's chest. Such a configuration canallow for over-the-wire placement of the catheter using astylet/guidewire as described here. As such, the above embodimentsshould not be construed as being limiting of the present invention inany way.

FIGS. 38-44 describe features of embodiments relating to a radiatingelement for use in assisting in the placement of an implantable medicaldevice, such as a catheter, within the body of a patient. The radiatingelement is capable of producing a detectable electromagnetic field andin one embodiment is included in a stylet. In particular, the styletincludes functionality to generate an electrical pulse signal to a coilassembly disposed at a distal end thereof. The resulting electromagneticfield produced by the coil assembly is detectable by the sensor unit ofthe catheter placement system generally described above, which is placedin proximate relation to the patient during catheter advancement. Thestylet including the coil assembly is positioned within the cathetersuch that the coil assembly is substantially co-terminal with the distalend of the catheter, thus enabling a clinician to determine anapproximate location and/or orientation of the catheter distal endduring advancement thereof through the patient vasculature and todetermine when a possible catheter malposition has occurred. As such,the stylet described here in connection with the present embodimentreplaces the stylet including a passive magnetic assembly described inprevious embodiments further above in connection with the catheterplacement system.

In accordance with one embodiment, the stylet including the radiatingelement is physically untethered to a console or other component of thecatheter placement system. Thus, the stylet itself includes allnecessary componentry for producing the electrical pulse signal for useby the system. The stylet in one embodiment further includesfunctionality to synchronize its pulsing activities with a console ofthe catheter placement system such that the system can accurately trackadvancement of the stylet and its corresponding catheter through thepatient vasculature. In another embodiment, the stylet including theradiating element is tethered to the sensor unit of the catheterplacement system in such a way as to enable the passage of drivingsignals from the sensor unit or system console to the radiating elementthrough a sterile barrier interposed between the catheter/stylet andsensor unit or console without compromising the barrier itself or thesterile field it helps establish.

Reference is made to FIGS. 1 and 38 which depict the various componentsof the catheter placement system (“system”) 10, configured in accordancewith one example embodiment, and as have already been described furtherabove. FIG. 38 shows the general relation of these components to thepatient 70 during a procedure to place the catheter 72 into the patientvasculature through the skin insertion site 73. As before, the system 10is employed in connection with positioning the distal tip 76A of thecatheter 72 in a desired position within the patient vasculature. In oneembodiment, the desired position for the catheter distal tip 76A isproximate the patient's heart, such as in the lower one-third portion ofthe SVC.

As mentioned above, the catheter placement system 10 includes a tiplocation system (“TLS”) modality that enables the clinician to quicklylocate and confirm the position and/or orientation of the catheter 72during initial placement into and advancement through the vasculature ofthe patient 70. Specifically, the TLS modality is configured to detectan electromagnetic field generated by the radiating element, such as acoil assembly included at a distal end of a stylet, which is pre-loadedin one embodiment into a longitudinally defined lumen of the catheter72, thus enabling the clinician to ascertain the general location andorientation of the catheter tip within the patient body. The TLS alsodisplays the direction in which the catheter tip is pointing, furtherassisting accurate catheter placement. In addition, the TLS assists theclinician in determining when a malposition of the catheter tip hasoccurred, such as in the case where the tip has deviated from a desiredvenous path into another vein.

As mentioned, the TLS utilizes a stylet in one embodiment to enable thedistal end of the catheter 72 to be tracked during its advancementthrough the vasculature. FIGS. 38 and 39 give an example of a detachedconfiguration of such a stylet 100, configured in accordance with oneembodiment. In particular, the stylet 100 in FIGS. 38 and 39 isphysically detached, or untethered, from other components of thecatheter placement system 10. The stylet 100 includes a proximal end100A and a distal end 100B. A stylet control module 102, also referredto herein as a “fob,” is included at the stylet proximal end 100A, withan elongate portion 1104 extending distally therefrom.

FIG. 40 gives further details regarding a distal portion of the styletelongate portion 104 proximate the stylet distal end 100B. A coilassembly 1106 is included proximate the stylet distal end 100B and isoperably connected to leads 1106A. The leads 1106A are in turn operablyconnected to corresponding circuitry located in the stylet controlmodule 102 configured to produce an electric pulse signal so as toenable the coil assembly 1106 to be electrically pulsed during operationand produce an electromagnetic field having a predetermined frequency orpattern that is detectable by one or more sensors included in the chestsensor 50 during transit of the catheter through the vasculature whenthe coil assembly is within the detectable range of the sensor. Notethat the coil assembly described herein is but one example of aradiating element, or a component capable of producing anelectromagnetic field for detection by the sensor. Indeed, other devicesand assembly designs can be utilized here to produce the same or similarfunctionality. For instance, non-limiting examples of other styletconfigurations can be found in U.S. patent application Ser. No.12/545,762, filed Aug. 21, 2009, and entitled “Catheter AssemblyIncluding ECG Sensor and Magnetic Assemblies,” which is incorporatedherein by reference in its entirety. In one embodiment, more than oneradiating element can be included, with each radiating element orientedin a different direction or spaced apart with respect to the other(s).In another embodiment, radiating elements of different types (e.g.,ultrasonic and electromagnetic) can be included together.

The coil assembly 1106 and leads 1106A are disposed within tubing 1108that extends at least a portion of the length of the stylet elongateportion 1104. The coil assembly and leads can be protected in other waysas well. A core wire 1110 can be included within the tubing 1108 in oneembodiment to offer stiffness and/or directional torqueability to thestylet elongate portion 1104. The core wire 1110 in one embodimentincludes nitinol and can extend to the distal end 100B of the stylet 100or terminate proximal thereto.

In accordance with the present embodiment, the stylet 100 is untethered,or physically unconnected, with respect to the console 20 of the system10. As such, the electric pulsing of the coil assembly 1106 to producethe predetermined electromagnetic field is driven by suitablecomponentry included in the fob, or stylet control module 102, asopposed to pulse driving by the console or other system component towhich the stylet would be physically connected. FIG. 41 shows suchcomponentry according to one example embodiment. The control module 102includes a housing 102A in which a printed circuit board (“PCB”) 1132 orother suitable platform is housed. Pulse circuitry 1134 is disposed onthe PCB 1132 and includes a timer circuit 1136 configured to provideelectrical pulses to the coil assembly 1106 via the leads 1106A (FIG.40). It is noted that in one embodiment the electromagnetic field can bepulsed so as to produce a predetermined pattern, if desired.

A connector 1130A is included on the control module housing 102A andconfigured to removably and operably connect with a correspondingconnector 1130B included on a proximal end of the stylet elongateportion 1104. In this way, operable connection between the timer circuit1136 and the coil assembly 1106 via the leads 1106A is achieved in thepresent embodiment. Note that other connective schemes between the pulsecircuitry and the coil assembly can be used. In another embodiment, thestylet elongate portion is permanently connected to the stylet controlmodule.

A power supply 1140 is included with the stylet control module 102 toprovide power necessary for control module functions, includingoperation of the pulse circuitry 1134 and driving of the electricpulsing performed by the timer circuit 1136. In one embodiment, thestylet 100 is a disposable, one-time use component and as such the powersupply 1140 is also disposable, such as a button-cell battery. In otherembodiments, the power supply can be a rechargeable battery, a long-lifepower supply, or can be configured to be replaceable as may beappreciated by one skilled in the art. In one embodiment, the controlmodule 102 includes an on/off switch for controlling operation of thecontrol module components.

As mentioned, the timer circuit 1136 drives the coil assembly 1106 bysending electrical pulses at a predetermined frequency to the coilassembly via the leads 1106A to which the timer circuit is operablyconnected. Receipt of the pulses causes the coil assembly 1106 to emitan electromagnetic field having the predetermined frequency that isdetectable by the sensor unit 50 of the system 10, thus assistingguidance of the catheter 72 (FIG. 38) as has been described.

In one embodiment, the electric pulse signal of the timer circuit 1136is synchronized with the console 20, or other system component (such asthe sensor 50), to enable the system 10 to identify the frequency of thefield produced by the coil assembly 1106 as a result of the pulsing.This enables the console 20 to identify the proper field relating to thestylet coil assembly 1106 and the sensor unit 50 to accurately trackprogress of the stylet 100 during intravascular advancement of thecatheter 72. The particular frequency/frequencies employed for the pulsesignal in one embodiment comply with applicable laws and regulations,including regulations promulgated by the Federal CommunicationsCommission (“FCC”). In one implementation a frequency of 1 MHz may beused, for example.

In the present embodiment, synchronization of the pulse signal frequencyproduced by the timer circuit 1136 with the console 20 is achieved by atransmitter 1138 included with the stylet control module 102, as seen inFIGS. 39 and 41. The transmitter 1138 is operably connected to andreceives data from the timer circuit 1136 relating to the frequency ofits pulse signal being sent to the coil assembly 1106. The transmitter1138 transmits the data to a receiver 1142 included on the console 20.Receiving the data by the receiver 1142, the console 20 can thenidentify the electromagnetic field produced by the coil assembly 1106when detected by the sensor unit 50 and thus track intravascularadvancement of the catheter 72.

In one implementation, the data transmitted by the transmitter 1138 area message detailing the pulsing frequency of the pulse signal producedby the timer circuit 1136. In another implementation, the data aremerely a replication of the pulse signal itself that, when received bythe console 20, enable the console to determine the frequency. Theconsole processor 22 (FIG. 1) or other suitable console circuitry can beemployed to perform this determination functionality. Of course, thedata can take any one of a variety of formats and configurations toenable information relating to the pulse signal to be received by theconsole or other suitable component of the system. In certainembodiments, the console 20, the sensor unit 50, or other suitablecomponent of the system 10 can include the necessary circuitry tosynchronize with the signal produced by the stylet 100, as describedherein.

The transmitter 1138 can transmit, and the receiver 1142 receive, theabove-referenced data in any number of ways, but in one implementationthe transmitter transmits via infrared (“IR”) or radiofrequency (“RF”)wavelengths for receipt by the receiver. As such, for example, thetransmitter 1138 and receiver 1142 can be configured as an IRLED/detector pair in the first case, or as an antenna pair in the secondcase. Note that other types of transmitter/receiver configurations canbe included to perform the intended functionality described herein.Other forms of electromagnetic radiation can be employed to transmitdata, including visible light in one embodiment.

In one embodiment, the timer circuit of the untethered stylet controlmodule is configured to be adjustable such that the pulse frequency canbe selected from a plurality of predetermined frequency options. Suchfunctionality may assist in the case where interference exists on one ormore of the predetermined frequencies, where different stylets are usedsuccessively by the same system, or where multiple systems are usedsimultaneously in close proximity to one another. In such aconfiguration, a selector switch may be included on the control modulehousing 102A, the console 20, and/or other suitable system component.The above or other suitable synchronization scheme can be used tocoordinate the selected pulse frequency to be transmitted and receivedbetween the stylet control module and the console.

In another implementation, the stylet control module/consoleautomatically switches to one of a plurality of possible pulsefrequencies for use in driving the coil assembly. In this latterimplementation, the console can be configured to successively scan theplurality of possible frequencies and perform frequency identificationfunctions, including phase locking, to identify the frequency on whichthe stylet control module timer circuit is producing the electricalpulse signal, thus enabling synchronization of the console therewith.

FIG. 42 shows an example of the above synchronization implementation,according to one embodiment. As shown, a transmitter such as an antenna1152 is included with the stylet control module 102 and is configured toemit radiofrequency (“RF”) or other suitable signals. A receiver such asan antenna 1161 is included with the console 20 of the system 10 toreceive signals emitted by the stylet control module antenna 1152. Theconsole further includes various components for processing signalsreceived by the antenna 1161, including a mixer 1163, an oscillator1165, a low pass filter 1166, an analog-to-digital converter (“ADC”)1167, and a digital signal processor (“DSP”) 1168.

During operation of the system 10, the stylet antenna 102B of the styletcontrol module 102 emits an RF or other suitable signal (e.g., infrared(“IR”)) that provides data relating to the frequency of the pulsesignal. The RF signal is received by the console antenna 1161. The mixer1163 combines the signal received by the antenna 1161 with apredetermined signal generated by the oscillator 1165, which combinedsignal is then filtered through the low pass filter 1166 to remove anyextraneous signals. The filtered and combined signal is passed throughthe ADC 1167, then analyzed by the DSP 1168 to determine whether the twosignals forming the combined signal match. If so, phase shifting of thesignals will be performed by the DSP and/or oscillator 1165 to lock thesignals in phase.

If the signals do not match, the above process is repeated with a newsignal having a different frequency being produced by the oscillator1165 until the signal. The above process is iteratively repeated untilthe signal from the oscillator matches in frequency the signal emittedby the stylet control module antenna 1152 and subsequently received bythe console antenna 1161. Thus, the oscillator 1165 in one embodiment iscapable of cycling through a plurality of pre-set signal frequencies inattempting to match the emitted signal of the stylet control moduleantenna 1152. In another embodiment, the oscillator can cycle through arange of frequencies in attempting to match the emitted signal. As notedbefore, once the proper signal frequency is determined by the console20, phase shifting as needed can be conducted to completesynchronization between the stylet 100 and the console 20, thus enablingthe console to track the distal end of the stylet 100.

It is understood that the above is merely one example of synchronizingthe pulse signal produced by the stylet coil assembly with the consoleand that other implementations can be employed to link the frequencybetween the stylet coil assembly and console or other component of thesystem.

In another embodiment, it is appreciated that the transmitter/receiverconfiguration can be reversed such that the transmitter is included withthe console and directs information regarding the frequency of the pulsesignal to the stylet control module, which receives the information viaa receiver included therein. In yet another embodiment, both the styletand the console are manufactured to operate with a pre-set pulse signalfrequency, requiring no subsequent synchronization therebetween. Theseand other possible configurations are therefore contemplated. Generally,it should be understood that the pulse circuitry and timer circuit ofthe stylet control module, together with the processor of the console20, can be configured in one or more of a variety of ways to achieveabove-described functionality. For instance, the processor 22 of theconsole 20 can be included in the sensor unit 50 (FIG. 1, 38) such thatsynchronization operations on behalf of the system 10 are performed bythe sensor. Or, in another embodiment the stylet functionality isincorporated into the catheter itself and no removable stylet isemployed.

Reference is again made to FIG. 38, which shows disposal of theuntethered stylet 100 substantially within a lumen in the catheter 72such that the proximal portion thereof, including the control module102, extends proximally beyond the catheter lumen, the hub 74A and aselected one of the extension legs 74B. So disposed within a lumen ofthe catheter, the coil assembly 1106 proximate the distal end 100B ofthe stylet 100 is substantially co-terminal with the distal catheter end76A such that detection by the TLS of the stylet coil assemblycorrespondingly indicates the location of the catheter distal end.

The TLS sensor unit 50 is employed by the system 10 during TLS operationto detect the electromagnetic field produced by the coil assembly 1106of the stylet 100. As seen in FIG. 38, the TLS sensor unit 50 is placedon the chest of the patient during catheter insertion. The TLS sensorunit 50 is placed on the chest of the patient in a predeterminedlocation, such as through the use of external body landmarks, to enablethe field of the stylet coil assembly 1106, disposed in the catheter 72as described above, to be detected during catheter transit through thepatient vasculature. Again, as the coil assembly 1106 is substantiallyco-terminal with the distal end 76A of the catheter 72 (FIG. 38),detection by the TLS sensor 50 of the field produced by the coilassembly provides information to the clinician as to the position andorientation of the catheter distal end 76A during its transit.

In greater detail, the TLS sensor unit 50 is operably connected to theconsole 20 of the system 10 via one or more of the ports 52, as shown inFIG. 1. Note that other connection schemes between the TLS sensor andthe system console can also be used without limitation. As justdescribed, the coil assembly 1106 is employed in the stylet 100 toenable the position of the catheter distal end 76A (FIG. 38) to beobservable relative to the TLS sensor unit 50 placed on the patient'schest. Detection by the TLS sensor unit 50 of the stylet coil assembly1106 is graphically displayed on the display 30 of the console 20 duringTLS mode, represented in FIGS. 6-8C, for example. In this way, aclinician placing the catheter is able to generally determine thelocation of the catheter distal end 76A within the patient vasculaturerelative to the TLS sensor unit 50 and detect when catheter malposition,such as advancement of the catheter along an undesired vein, isoccurring. It should be appreciated that in one embodiment the positionsof the radiating element and the sensor can be reversed such thatremotely powered sensor is included with the stylet for detecting afield produced by the radiating element positioned external to the bodyof the patient.

As mentioned further above, note that the system 10 in one embodimentcan include additional functionality wherein determination of theproximity of the catheter distal tip 76A relative to a sino-atrial(“SA”) or other electrical impulse-emitting node of the heart of thepatient 70 can be determined, thus providing enhanced ability toaccurately place the catheter distal tip in a desired location proximatethe node. Also referred to as “ECG” or “ECG-based tip confirmation,”this third modality of the system can enable detection of ECG signalsfrom the SA node in order to place the catheter distal tip in a desiredlocation within the patient vasculature. Note that any functionality ofan ECG sensor included with the stylet may be incorporated with thestylet control module to provide a wireless pathway for transmitting ECGsensor data from the stylet ECG sensor to the system console, the TLSsensor, or other system component in conjunction with catheter placementprocedures. Such functionality can be in addition to the inclusion of aradiating element, such as the coil assembly spoken of herein. Notefurther that, in one embodiment, the control module housing can furtherserve as a handle to assist in manipulating the catheter and/or styletduring intravascular advancement.

The untethered stylet associated with the system as describedimmediately above herein allows for simple management of the sterilefield that is established about the insertion site 73 of the patient 70(FIG. 38) during the catheter placement procedure by eliminating wiresinterconnecting the stylet and the console that would have to penetratethrough the sterile field. FIGS. 43A-44 provide yet another solution foroperably interconnecting a radiating element included with a stylet orother suitable device through the sterile field of the patient withoutcompromising the sterility of the field, according to one embodiment. Inparticular the proximal end 100A of the stylet 100, instead of includinga control module 102, rather includes a tether connector 2132 configuredfor operably connecting to a corresponding sensor unit connector 2156disposed on the sensor unit 50, as shown in FIG. 43A. The tetherconnector 2132 in the present embodiment is operably connected to thedistal portion of the stylet 100 via a tether 2134. Note that, thoughconfigured similarly to the tether connector 132 and fin connector 156shown in FIGS. 14A-14C in connection with the ECG modality of thecatheter placement system 10 as described further above, the tetherconnector 2132 and sensor connector 2156 that enable operable connectionof the radiating element with the sensor unit 50 can be configured inother ways. As such, the discussion here is understood to describemerely one possible example of operable interconnection of a radiatingelement of a stylet or medical device with a sensor unit or othersuitable component of a catheter placement system. Many other types ofoperable interconnection can be employed, as appreciated by one skilledin the art.

FIG. 43B shows the slide-on manner of connection of the tether connector2132 with the sensor connector 2156 of the sensor unit 50. FIG. 44 showsa cross sectional view of the interconnection of the tether connector2132 with the sensor connector 2156, wherein a channel 2172 of thetether connector includes a piercing element, such as a pin contact2170, which extends into the channel. The drape 174 that covers thesensor unit 50 when the sensor unit is placed on the chest or otherportion of the body of the patient is interposed between the tetherconnector 2132 and the sensor connector 2156 when the tether connectoris slid on the sensor connector such that the pin contact 2170 piercesthe drape, extends past a centering cone 2164 and through a hole 2162defined in the sensor connector. Once the tether connector 2132 isseated on the sensor connector 2156, the pin contact 2170, which iselectrically bifurcated, physically contacts two contacts 2168 disposedin the sensor connector so as to enable a suitable closed circuit to beestablished therebetween. In this way, the radiating element, e.g., thecoil 1106, of the stylet 100 is operably connected via the tether 2134and connectors 2132/2156 with the necessary driving circuitry fordriving the coil, which circuitry can be located in the sensor unit 50,console 20, etc.

Furthermore, the interconnection of the tether connector 2132 with thesensor connector 2156 is established through the drape 174 withoutcompromising the barrier provided by the drape for establishingsterility about the catheter insertion site 73 (FIG. 38), similar toprevious embodiments discussed further above in connection with the ECGmodality of the catheter placement system 10. Indeed, the tetherconnector 2132 desirably covers and isolates the drape breach made bythe piercing pin contact 2170. Again, other types of through-drapeconnective schemes can be employed for operably connecting the radiatingelement with the sensor unit without compromising the sterile field.

Thus, in one embodiment, a method for operably connecting a radiatingelement with a sensor unit includes positioning the sensor unit on thepatient, placing the sterile barrier over the sensor unit, and operablyconnecting the radiating element to the sensor unit by penetrating thesterile barrier.

Although the embodiments described herein relate to a particularconfiguration of a catheter, such as a PICC or CVC, such embodiments aremerely exemplary. Accordingly, the principles of the present inventioncan be extended to catheters of many different configurations anddesigns.

Embodiments of the invention may be embodied in other specific formswithout departing from the spirit of the present disclosure. Thedescribed embodiments are to be considered in all respects only asillustrative, not restrictive. The scope of the embodiments is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A system for placing a catheter in a patient'svasculature, comprising: a console including a display; an ultrasoundprobe operably connected to the console for ultrasonically imaging aportion of the vasculature for depiction on the display; a radiatingelement included with the catheter, the radiating element capable ofproducing an electromagnetic field; and an external sensor unit operablyconnected to the console for depiction on the display of informationrelating to detection by the sensor unit of the electromagnetic field ofthe radiating element so as to determine a position of the catheter withrespect to the external sensor during advancement of the catheter in thevasculature.
 2. The placement system according to claim 1, wherein theradiating element is included with a stylet that is removablypositionable in a lumen of the catheter, and wherein the stylet includesa first connector.
 3. The placement system according to claim 2, whereinthe stylet is positioned within a sterile field, wherein the sensor unitis positioned outside of the sterile field, and wherein the sensor unitincludes a second connector that operably connects to the firstconnector of the stylet through a sterile barrier without compromisingthe sterile barrier.
 4. The placement system according to claim 3,wherein the sterile barrier comprises a physical barrier, and one of thefirst and second connectors includes a piercing component that piercesthe physical barrier.
 5. The placement system according to claim 3,wherein the radiating element of the stylet includes an electromagneticcoil that is substantially co-terminal with a distal tip of the catheterwhen the stylet is positioned in the lumen of the catheter, wherein thesterile barrier is a drape, and wherein the first connector includes apiercing component that pierces the drape.
 6. The placement systemaccording to claim 5, wherein the piercing component includes a firstelectrical contact that physically engages a second electrical contactof the second connector to electrically interconnect the first andsecond connectors.
 7. The placement system according to claim 1, furthercomprising a control module for controlling operation of the radiatingelement.
 8. The placement system according to claim 7, wherein thecontrol module is capable of wirelessly transmitting at least onecharacteristic of the electromagnetic field produced by the radiatingelement.
 9. The placement system according to claim 8, wherein the atleast one characteristic is wirelessly transmitted between the controlmodule and a component of a system for assisting in placement of thecatheter.
 10. The placement system according to claim 9, wherein the atleast one characteristic that is wirelessly transmitted is transmittedusing one of visible, infrared, and RF radiation.
 11. The placementsystem according to claim 8, further comprising a phase locking circuitfor synchronizing a frequency of the electromagnetic field produced bythe radiating element.
 12. A method for placing a catheter in apatient's vasculature, comprising: visualizing a portion of thevasculature using an ultrasound probe; introducing a catheter includinga radiating element into the vasculature, the radiating elementconfigured to produce an electromagnetic field; positioning a sensorunit on the patient, the sensor unit configured to detect theelectromagnetic field of the radiating element; advancing the catheterand radiating element through the vasculature; and determining aposition of the catheter with respect to the sensor unit during theadvancing.
 13. The method according to claim 12, wherein the radiatingelement is incorporated into a stylet that is removably positioned in alumen of the catheter, wherein the stylet includes a first connector,and wherein the sensor unit includes a second connector, the methodfurther comprising: placing a sterile barrier over the sensor unit; andconnecting the first and second connectors through the sterile barrier.14. The method according to claim 13, wherein the sterile barrierincludes a drape, wherein one of the first and second connectorsincludes a piercing component, the connecting step comprisingpenetrating the drape with the piercing component without compromisingthe sterile barrier.
 15. The method according to claim 13, wherein theconnecting comprises electrically connecting the sensor unit to theradiating element.